diff --git a/internal/auth/auth.go b/internal/auth/auth.go
index c6cb90e..5d94735 100644
--- a/internal/auth/auth.go
+++ b/internal/auth/auth.go
@@ -18,7 +18,6 @@ import (
 	"net"
 	"net/http"
 	"os"
-	"strings"
 	"sync"
 	"time"
 
@@ -32,8 +31,19 @@ import (
 	"github.com/gorilla/sessions"
 )
 
+// Authenticator is the interface for all authentication methods.
+// Each authenticator determines if it can handle a login request (CanLogin)
+// and performs the actual authentication (Login).
 type Authenticator interface {
+	// CanLogin determines if this authenticator can handle the login request.
+	// It returns the user object if available and a boolean indicating if this
+	// authenticator should attempt the login. This method should not perform
+	// expensive operations or actual authentication.
 	CanLogin(user *schema.User, username string, rw http.ResponseWriter, r *http.Request) (*schema.User, bool)
+	
+	// Login performs the actually authentication for the user.
+	// It returns the authenticated user or an error if authentication fails.
+	// The user parameter may be nil if the user doesn't exist in the database yet.
 	Login(user *schema.User, rw http.ResponseWriter, r *http.Request) (*schema.User, error)
 }
 
@@ -42,27 +52,70 @@ var (
 	authInstance *Authentication
 )
 
-var ipUserLimiters sync.Map
-
-func getIPUserLimiter(ip, username string) *rate.Limiter {
-	key := ip + ":" + username
-	limiter, ok := ipUserLimiters.Load(key)
-	if !ok {
-		newLimiter := rate.NewLimiter(rate.Every(time.Hour/10), 10)
-		ipUserLimiters.Store(key, newLimiter)
-		return newLimiter
-	}
-	return limiter.(*rate.Limiter)
+// rateLimiterEntry tracks a rate limiter and its last use time for cleanup
+type rateLimiterEntry struct {
+	limiter  *rate.Limiter
+	lastUsed time.Time
 }
 
+var ipUserLimiters sync.Map
+
+// getIPUserLimiter returns a rate limiter for the given IP and username combination.
+// Rate limiters are created on demand and track 5 attempts per 15 minutes.
+func getIPUserLimiter(ip, username string) *rate.Limiter {
+	key := ip + ":" + username
+	now := time.Now()
+	
+	if entry, ok := ipUserLimiters.Load(key); ok {
+		rle := entry.(*rateLimiterEntry)
+		rle.lastUsed = now
+		return rle.limiter
+	}
+	
+	// More aggressive rate limiting: 5 attempts per 15 minutes
+	newLimiter := rate.NewLimiter(rate.Every(15*time.Minute/5), 5)
+	ipUserLimiters.Store(key, &rateLimiterEntry{
+		limiter:  newLimiter,
+		lastUsed: now,
+	})
+	return newLimiter
+}
+
+// cleanupOldRateLimiters removes rate limiters that haven't been used recently
+func cleanupOldRateLimiters(olderThan time.Time) {
+	ipUserLimiters.Range(func(key, value any) bool {
+		entry := value.(*rateLimiterEntry)
+		if entry.lastUsed.Before(olderThan) {
+			ipUserLimiters.Delete(key)
+			cclog.Debugf("Cleaned up rate limiter for %v", key)
+		}
+		return true
+	})
+}
+
+// startRateLimiterCleanup starts a background goroutine to clean up old rate limiters
+func startRateLimiterCleanup() {
+	go func() {
+		ticker := time.NewTicker(1 * time.Hour)
+		defer ticker.Stop()
+		for range ticker.C {
+			// Clean up limiters not used in the last 24 hours
+			cleanupOldRateLimiters(time.Now().Add(-24 * time.Hour))
+		}
+	}()
+}
+
+// AuthConfig contains configuration for all authentication methods
 type AuthConfig struct {
 	LdapConfig   *LdapConfig    `json:"ldap"`
 	JwtConfig    *JWTAuthConfig `json:"jwts"`
 	OpenIDConfig *OpenIDConfig  `json:"oidc"`
 }
 
+// Keys holds the global authentication configuration
 var Keys AuthConfig
 
+// Authentication manages all authentication methods and session handling
 type Authentication struct {
 	sessionStore   *sessions.CookieStore
 	LdapAuth       *LdapAuthenticator
@@ -86,10 +139,31 @@ func (auth *Authentication) AuthViaSession(
 		return nil, nil
 	}
 
-	// TODO: Check if session keys exist
-	username, _ := session.Values["username"].(string)
-	projects, _ := session.Values["projects"].([]string)
-	roles, _ := session.Values["roles"].([]string)
+	// Validate session data with proper type checking
+	username, ok := session.Values["username"].(string)
+	if !ok || username == "" {
+		cclog.Warn("Invalid session: missing or invalid username")
+		// Invalidate the corrupted session
+		session.Options.MaxAge = -1
+		_ = auth.sessionStore.Save(r, rw, session)
+		return nil, errors.New("invalid session data")
+	}
+
+	projects, ok := session.Values["projects"].([]string)
+	if !ok {
+		cclog.Warn("Invalid session: projects not found or invalid type, using empty list")
+		projects = []string{}
+	}
+
+	roles, ok := session.Values["roles"].([]string)
+	if !ok || len(roles) == 0 {
+		cclog.Warn("Invalid session: missing or invalid roles")
+		// Invalidate the corrupted session
+		session.Options.MaxAge = -1
+		_ = auth.sessionStore.Save(r, rw, session)
+		return nil, errors.New("invalid session data")
+	}
+
 	return &schema.User{
 		Username:   username,
 		Projects:   projects,
@@ -102,6 +176,9 @@ func (auth *Authentication) AuthViaSession(
 func Init(authCfg *json.RawMessage) {
 	initOnce.Do(func() {
 		authInstance = &Authentication{}
+		
+		// Start background cleanup of rate limiters
+		startRateLimiterCleanup()
 
 		sessKey := os.Getenv("SESSION_KEY")
 		if sessKey == "" {
@@ -185,38 +262,36 @@ func GetAuthInstance() *Authentication {
 	return authInstance
 }
 
-func handleTokenUser(tokenUser *schema.User) {
+// handleUserSync syncs or updates a user in the database based on configuration.
+// This is used for both JWT and OIDC authentication when syncUserOnLogin or updateUserOnLogin is enabled.
+func handleUserSync(user *schema.User, syncUserOnLogin, updateUserOnLogin bool) {
 	r := repository.GetUserRepository()
-	dbUser, err := r.GetUser(tokenUser.Username)
+	dbUser, err := r.GetUser(user.Username)
 
 	if err != nil && err != sql.ErrNoRows {
-		cclog.Errorf("Error while loading user '%s': %v", tokenUser.Username, err)
-	} else if err == sql.ErrNoRows && Keys.JwtConfig.SyncUserOnLogin { // Adds New User
-		if err := r.AddUser(tokenUser); err != nil {
-			cclog.Errorf("Error while adding user '%s' to DB: %v", tokenUser.Username, err)
+		cclog.Errorf("Error while loading user '%s': %v", user.Username, err)
+		return
+	}
+	
+	if err == sql.ErrNoRows && syncUserOnLogin { // Add new user
+		if err := r.AddUser(user); err != nil {
+			cclog.Errorf("Error while adding user '%s' to DB: %v", user.Username, err)
 		}
-	} else if err == nil && Keys.JwtConfig.UpdateUserOnLogin { // Update Existing User
-		if err := r.UpdateUser(dbUser, tokenUser); err != nil {
-			cclog.Errorf("Error while updating user '%s' to DB: %v", dbUser.Username, err)
+	} else if err == nil && updateUserOnLogin { // Update existing user
+		if err := r.UpdateUser(dbUser, user); err != nil {
+			cclog.Errorf("Error while updating user '%s' in DB: %v", dbUser.Username, err)
 		}
 	}
 }
 
-func handleOIDCUser(OIDCUser *schema.User) {
-	r := repository.GetUserRepository()
-	dbUser, err := r.GetUser(OIDCUser.Username)
+// handleTokenUser syncs JWT token user with database
+func handleTokenUser(tokenUser *schema.User) {
+	handleUserSync(tokenUser, Keys.JwtConfig.SyncUserOnLogin, Keys.JwtConfig.UpdateUserOnLogin)
+}
 
-	if err != nil && err != sql.ErrNoRows {
-		cclog.Errorf("Error while loading user '%s': %v", OIDCUser.Username, err)
-	} else if err == sql.ErrNoRows && Keys.OpenIDConfig.SyncUserOnLogin { // Adds New User
-		if err := r.AddUser(OIDCUser); err != nil {
-			cclog.Errorf("Error while adding user '%s' to DB: %v", OIDCUser.Username, err)
-		}
-	} else if err == nil && Keys.OpenIDConfig.UpdateUserOnLogin { // Update Existing User
-		if err := r.UpdateUser(dbUser, OIDCUser); err != nil {
-			cclog.Errorf("Error while updating user '%s' to DB: %v", dbUser.Username, err)
-		}
-	}
+// handleOIDCUser syncs OIDC user with database
+func handleOIDCUser(OIDCUser *schema.User) {
+	handleUserSync(OIDCUser, Keys.OpenIDConfig.SyncUserOnLogin, Keys.OpenIDConfig.UpdateUserOnLogin)
 }
 
 func (auth *Authentication) SaveSession(rw http.ResponseWriter, r *http.Request, user *schema.User) error {
@@ -231,6 +306,7 @@ func (auth *Authentication) SaveSession(rw http.ResponseWriter, r *http.Request,
 		session.Options.MaxAge = int(auth.SessionMaxAge.Seconds())
 	}
 	if config.Keys.HTTPSCertFile == "" && config.Keys.HTTPSKeyFile == "" {
+		cclog.Warn("HTTPS not configured - session cookies will not have Secure flag set (insecure for production)")
 		session.Options.Secure = false
 	}
 	session.Options.SameSite = http.SameSiteStrictMode
@@ -532,10 +608,13 @@ func securedCheck(user *schema.User, r *http.Request) error {
 		IPAddress = r.RemoteAddr
 	}
 
-	// FIXME: IPV6 not handled
-	if strings.Contains(IPAddress, ":") {
-		IPAddress = strings.Split(IPAddress, ":")[0]
+	// Handle both IPv4 and IPv6 addresses properly
+	// For IPv6, this will strip the port and brackets
+	// For IPv4, this will strip the port
+	if host, _, err := net.SplitHostPort(IPAddress); err == nil {
+		IPAddress = host
 	}
+	// If SplitHostPort fails, IPAddress is already just a host (no port)
 
 	// If nothing declared in config: deny all request to this api endpoint
 	if len(config.Keys.APIAllowedIPs) == 0 {
diff --git a/internal/auth/auth_test.go b/internal/auth/auth_test.go
new file mode 100644
index 0000000..15f153e
--- /dev/null
+++ b/internal/auth/auth_test.go
@@ -0,0 +1,176 @@
+// Copyright (C) NHR@FAU, University Erlangen-Nuremberg.
+// All rights reserved. This file is part of cc-backend.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package auth
+
+import (
+	"net"
+	"testing"
+	"time"
+)
+
+// TestGetIPUserLimiter tests the rate limiter creation and retrieval
+func TestGetIPUserLimiter(t *testing.T) {
+	ip := "192.168.1.1"
+	username := "testuser"
+	
+	// Get limiter for the first time
+	limiter1 := getIPUserLimiter(ip, username)
+	if limiter1 == nil {
+		t.Fatal("Expected limiter to be created")
+	}
+	
+	// Get the same limiter again
+	limiter2 := getIPUserLimiter(ip, username)
+	if limiter1 != limiter2 {
+		t.Error("Expected to get the same limiter instance")
+	}
+	
+	// Get a different limiter for different user
+	limiter3 := getIPUserLimiter(ip, "otheruser")
+	if limiter1 == limiter3 {
+		t.Error("Expected different limiter for different user")
+	}
+	
+	// Get a different limiter for different IP
+	limiter4 := getIPUserLimiter("192.168.1.2", username)
+	if limiter1 == limiter4 {
+		t.Error("Expected different limiter for different IP")
+	}
+}
+
+// TestRateLimiterBehavior tests that rate limiting works correctly
+func TestRateLimiterBehavior(t *testing.T) {
+	ip := "10.0.0.1"
+	username := "ratelimituser"
+	
+	limiter := getIPUserLimiter(ip, username)
+	
+	// Should allow first 5 attempts
+	for i := 0; i < 5; i++ {
+		if !limiter.Allow() {
+			t.Errorf("Request %d should be allowed within rate limit", i+1)
+		}
+	}
+	
+	// 6th attempt should be blocked
+	if limiter.Allow() {
+		t.Error("Request 6 should be blocked by rate limiter")
+	}
+}
+
+// TestCleanupOldRateLimiters tests the cleanup function
+func TestCleanupOldRateLimiters(t *testing.T) {
+	// Clear all existing limiters first to avoid interference from other tests
+	cleanupOldRateLimiters(time.Now().Add(24 * time.Hour))
+	
+	// Create some new rate limiters
+	limiter1 := getIPUserLimiter("1.1.1.1", "user1")
+	limiter2 := getIPUserLimiter("2.2.2.2", "user2")
+	
+	if limiter1 == nil || limiter2 == nil {
+		t.Fatal("Failed to create test limiters")
+	}
+	
+	// Cleanup limiters older than 1 second from now (should keep both)
+	time.Sleep(10 * time.Millisecond) // Small delay to ensure timestamp difference
+	cleanupOldRateLimiters(time.Now().Add(-1 * time.Second))
+	
+	// Verify they still exist (should get same instance)
+	if getIPUserLimiter("1.1.1.1", "user1") != limiter1 {
+		t.Error("Limiter 1 was incorrectly cleaned up")
+	}
+	if getIPUserLimiter("2.2.2.2", "user2") != limiter2 {
+		t.Error("Limiter 2 was incorrectly cleaned up")
+	}
+	
+	// Cleanup limiters older than 1 hour from now (should remove both)
+	cleanupOldRateLimiters(time.Now().Add(2 * time.Hour))
+	
+	// Getting them again should create new instances
+	newLimiter1 := getIPUserLimiter("1.1.1.1", "user1")
+	if newLimiter1 == limiter1 {
+		t.Error("Old limiter should have been cleaned up")
+	}
+}
+
+// TestIPv4Extraction tests extracting IPv4 addresses
+func TestIPv4Extraction(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    string
+		expected string
+	}{
+		{"IPv4 with port", "192.168.1.1:8080", "192.168.1.1"},
+		{"IPv4 without port", "192.168.1.1", "192.168.1.1"},
+		{"Localhost with port", "127.0.0.1:3000", "127.0.0.1"},
+	}
+	
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := tt.input
+			if host, _, err := net.SplitHostPort(result); err == nil {
+				result = host
+			}
+			
+			if result != tt.expected {
+				t.Errorf("Expected %s, got %s", tt.expected, result)
+			}
+		})
+	}
+}
+
+// TestIPv6Extraction tests extracting IPv6 addresses  
+func TestIPv6Extraction(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    string
+		expected string
+	}{
+		{"IPv6 with port", "[2001:db8::1]:8080", "2001:db8::1"},
+		{"IPv6 localhost with port", "[::1]:3000", "::1"},
+		{"IPv6 without port", "2001:db8::1", "2001:db8::1"},
+		{"IPv6 localhost", "::1", "::1"},
+	}
+	
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := tt.input
+			if host, _, err := net.SplitHostPort(result); err == nil {
+				result = host
+			}
+			
+			if result != tt.expected {
+				t.Errorf("Expected %s, got %s", tt.expected, result)
+			}
+		})
+	}
+}
+
+// TestIPExtractionEdgeCases tests edge cases for IP extraction
+func TestIPExtractionEdgeCases(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    string
+		expected string
+	}{
+		{"Hostname without port", "example.com", "example.com"},
+		{"Empty string", "", ""},
+		{"Just port", ":8080", ""},
+	}
+	
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := tt.input
+			if host, _, err := net.SplitHostPort(result); err == nil {
+				result = host
+			}
+			
+			if result != tt.expected {
+				t.Errorf("Expected %s, got %s", tt.expected, result)
+			}
+		})
+	}
+}
diff --git a/internal/auth/jwt.go b/internal/auth/jwt.go
index 7d7a047..4f1f3f5 100644
--- a/internal/auth/jwt.go
+++ b/internal/auth/jwt.go
@@ -14,7 +14,6 @@ import (
 	"strings"
 	"time"
 
-	"github.com/ClusterCockpit/cc-backend/internal/repository"
 	cclog "github.com/ClusterCockpit/cc-lib/ccLogger"
 	"github.com/ClusterCockpit/cc-lib/schema"
 	"github.com/golang-jwt/jwt/v5"
@@ -102,38 +101,21 @@ func (ja *JWTAuthenticator) AuthViaJWT(
 
 	// Token is valid, extract payload
 	claims := token.Claims.(jwt.MapClaims)
-	sub, _ := claims["sub"].(string)
-
-	var roles []string
-
-	// Validate user + roles from JWT against database?
-	if Keys.JwtConfig.ValidateUser {
-		ur := repository.GetUserRepository()
-		user, err := ur.GetUser(sub)
-		// Deny any logins for unknown usernames
-		if err != nil {
-			cclog.Warn("Could not find user from JWT in internal database.")
-			return nil, errors.New("unknown user")
-		}
-		// Take user roles from database instead of trusting the JWT
-		roles = user.Roles
-	} else {
-		// Extract roles from JWT (if present)
-		if rawroles, ok := claims["roles"].([]any); ok {
-			for _, rr := range rawroles {
-				if r, ok := rr.(string); ok {
-					roles = append(roles, r)
-				}
-			}
-		}
+	
+	// Use shared helper to get user from JWT claims
+	var user *schema.User
+	user, err = getUserFromJWT(claims, Keys.JwtConfig.ValidateUser, schema.AuthToken, -1)
+	if err != nil {
+		return nil, err
 	}
-
-	return &schema.User{
-		Username:   sub,
-		Roles:      roles,
-		AuthType:   schema.AuthToken,
-		AuthSource: -1,
-	}, nil
+	
+	// If not validating user, we only get roles from JWT (no projects for this auth method)
+	if !Keys.JwtConfig.ValidateUser {
+		user.Roles = extractRolesFromClaims(claims, false)
+		user.Projects = nil // Standard JWT auth doesn't include projects
+	}
+	
+	return user, nil
 }
 
 // ProvideJWT generates a new JWT that can be used for authentication
diff --git a/internal/auth/jwtCookieSession.go b/internal/auth/jwtCookieSession.go
index 300f875..44c64a0 100644
--- a/internal/auth/jwtCookieSession.go
+++ b/internal/auth/jwtCookieSession.go
@@ -7,14 +7,11 @@ package auth
 
 import (
 	"crypto/ed25519"
-	"database/sql"
 	"encoding/base64"
 	"errors"
-	"fmt"
 	"net/http"
 	"os"
 
-	"github.com/ClusterCockpit/cc-backend/internal/repository"
 	cclog "github.com/ClusterCockpit/cc-lib/ccLogger"
 	"github.com/ClusterCockpit/cc-lib/schema"
 	"github.com/golang-jwt/jwt/v5"
@@ -149,57 +146,16 @@ func (ja *JWTCookieSessionAuthenticator) Login(
 	}
 
 	claims := token.Claims.(jwt.MapClaims)
-	sub, _ := claims["sub"].(string)
-
-	var roles []string
-	projects := make([]string, 0)
-
-	if jc.ValidateUser {
-		var err error
-		user, err = repository.GetUserRepository().GetUser(sub)
-		if err != nil && err != sql.ErrNoRows {
-			cclog.Errorf("Error while loading user '%v'", sub)
-		}
-
-		// Deny any logins for unknown usernames
-		if user == nil {
-			cclog.Warn("Could not find user from JWT in internal database.")
-			return nil, errors.New("unknown user")
-		}
-	} else {
-		var name string
-		if wrap, ok := claims["name"].(map[string]any); ok {
-			if vals, ok := wrap["values"].([]any); ok {
-				if len(vals) != 0 {
-					name = fmt.Sprintf("%v", vals[0])
-
-					for i := 1; i < len(vals); i++ {
-						name += fmt.Sprintf(" %v", vals[i])
-					}
-				}
-			}
-		}
-
-		// Extract roles from JWT (if present)
-		if rawroles, ok := claims["roles"].([]any); ok {
-			for _, rr := range rawroles {
-				if r, ok := rr.(string); ok {
-					roles = append(roles, r)
-				}
-			}
-		}
-		user = &schema.User{
-			Username:   sub,
-			Name:       name,
-			Roles:      roles,
-			Projects:   projects,
-			AuthType:   schema.AuthSession,
-			AuthSource: schema.AuthViaToken,
-		}
-
-		if jc.SyncUserOnLogin || jc.UpdateUserOnLogin {
-			handleTokenUser(user)
-		}
+	
+	// Use shared helper to get user from JWT claims
+	user, err = getUserFromJWT(claims, jc.ValidateUser, schema.AuthSession, schema.AuthViaToken)
+	if err != nil {
+		return nil, err
+	}
+	
+	// Sync or update user if configured
+	if !jc.ValidateUser && (jc.SyncUserOnLogin || jc.UpdateUserOnLogin) {
+		handleTokenUser(user)
 	}
 
 	// (Ask browser to) Delete JWT cookie
diff --git a/internal/auth/jwtHelpers.go b/internal/auth/jwtHelpers.go
new file mode 100644
index 0000000..792722a
--- /dev/null
+++ b/internal/auth/jwtHelpers.go
@@ -0,0 +1,136 @@
+// Copyright (C) NHR@FAU, University Erlangen-Nuremberg.
+// All rights reserved. This file is part of cc-backend.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package auth
+
+import (
+	"database/sql"
+	"errors"
+	"fmt"
+
+	"github.com/ClusterCockpit/cc-backend/internal/repository"
+	cclog "github.com/ClusterCockpit/cc-lib/ccLogger"
+	"github.com/ClusterCockpit/cc-lib/schema"
+	"github.com/golang-jwt/jwt/v5"
+)
+
+// extractStringFromClaims extracts a string value from JWT claims
+func extractStringFromClaims(claims jwt.MapClaims, key string) string {
+	if val, ok := claims[key].(string); ok {
+		return val
+	}
+	return ""
+}
+
+// extractRolesFromClaims extracts roles from JWT claims
+// If validateRoles is true, only valid roles are returned
+func extractRolesFromClaims(claims jwt.MapClaims, validateRoles bool) []string {
+	var roles []string
+	
+	if rawroles, ok := claims["roles"].([]any); ok {
+		for _, rr := range rawroles {
+			if r, ok := rr.(string); ok {
+				if validateRoles {
+					if schema.IsValidRole(r) {
+						roles = append(roles, r)
+					}
+				} else {
+					roles = append(roles, r)
+				}
+			}
+		}
+	}
+	
+	return roles
+}
+
+// extractProjectsFromClaims extracts projects from JWT claims
+func extractProjectsFromClaims(claims jwt.MapClaims) []string {
+	projects := make([]string, 0)
+	
+	if rawprojs, ok := claims["projects"].([]any); ok {
+		for _, pp := range rawprojs {
+			if p, ok := pp.(string); ok {
+				projects = append(projects, p)
+			}
+		}
+	} else if rawprojs, ok := claims["projects"]; ok {
+		if projSlice, ok := rawprojs.([]string); ok {
+			projects = append(projects, projSlice...)
+		}
+	}
+	
+	return projects
+}
+
+// extractNameFromClaims extracts name from JWT claims
+// Handles both simple string and complex nested structure
+func extractNameFromClaims(claims jwt.MapClaims) string {
+	// Try simple string first
+	if name, ok := claims["name"].(string); ok {
+		return name
+	}
+	
+	// Try nested structure: {name: {values: [...]}}
+	if wrap, ok := claims["name"].(map[string]any); ok {
+		if vals, ok := wrap["values"].([]any); ok {
+			if len(vals) == 0 {
+				return ""
+			}
+			
+			name := fmt.Sprintf("%v", vals[0])
+			for i := 1; i < len(vals); i++ {
+				name += fmt.Sprintf(" %v", vals[i])
+			}
+			return name
+		}
+	}
+	
+	return ""
+}
+
+// getUserFromJWT creates or retrieves a user based on JWT claims
+// If validateUser is true, the user must exist in the database
+// Otherwise, a new user object is created from claims
+// authSource should be a schema.AuthSource constant (like schema.AuthViaToken)
+func getUserFromJWT(claims jwt.MapClaims, validateUser bool, authType schema.AuthType, authSource schema.AuthSource) (*schema.User, error) {
+	sub := extractStringFromClaims(claims, "sub")
+	if sub == "" {
+		return nil, errors.New("missing 'sub' claim in JWT")
+	}
+	
+	if validateUser {
+		// Validate user against database
+		ur := repository.GetUserRepository()
+		user, err := ur.GetUser(sub)
+		if err != nil && err != sql.ErrNoRows {
+			cclog.Errorf("Error while loading user '%v': %v", sub, err)
+			return nil, fmt.Errorf("database error: %w", err)
+		}
+		
+		// Deny any logins for unknown usernames
+		if user == nil || err == sql.ErrNoRows {
+			cclog.Warn("Could not find user from JWT in internal database.")
+			return nil, errors.New("unknown user")
+		}
+		
+		// Return database user (with database roles)
+		return user, nil
+	}
+	
+	// Create user from JWT claims
+	name := extractNameFromClaims(claims)
+	roles := extractRolesFromClaims(claims, true) // Validate roles
+	projects := extractProjectsFromClaims(claims)
+	
+	return &schema.User{
+		Username:   sub,
+		Name:       name,
+		Roles:      roles,
+		Projects:   projects,
+		AuthType:   authType,
+		AuthSource: authSource,
+	}, nil
+}
diff --git a/internal/auth/jwtHelpers_test.go b/internal/auth/jwtHelpers_test.go
new file mode 100644
index 0000000..5cee1df
--- /dev/null
+++ b/internal/auth/jwtHelpers_test.go
@@ -0,0 +1,281 @@
+// Copyright (C) NHR@FAU, University Erlangen-Nuremberg.
+// All rights reserved. This file is part of cc-backend.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package auth
+
+import (
+	"testing"
+
+	"github.com/ClusterCockpit/cc-lib/schema"
+	"github.com/golang-jwt/jwt/v5"
+)
+
+// TestExtractStringFromClaims tests extracting string values from JWT claims
+func TestExtractStringFromClaims(t *testing.T) {
+	claims := jwt.MapClaims{
+		"sub":   "testuser",
+		"email": "test@example.com",
+		"age":   25, // not a string
+	}
+	
+	tests := []struct {
+		name     string
+		key      string
+		expected string
+	}{
+		{"Existing string", "sub", "testuser"},
+		{"Another string", "email", "test@example.com"},
+		{"Non-existent key", "missing", ""},
+		{"Non-string value", "age", ""},
+	}
+	
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := extractStringFromClaims(claims, tt.key)
+			if result != tt.expected {
+				t.Errorf("Expected %s, got %s", tt.expected, result)
+			}
+		})
+	}
+}
+
+// TestExtractRolesFromClaims tests role extraction and validation
+func TestExtractRolesFromClaims(t *testing.T) {
+	tests := []struct {
+		name          string
+		claims        jwt.MapClaims
+		validateRoles bool
+		expected      []string
+	}{
+		{
+			name: "Valid roles without validation",
+			claims: jwt.MapClaims{
+				"roles": []any{"admin", "user", "invalid_role"},
+			},
+			validateRoles: false,
+			expected:      []string{"admin", "user", "invalid_role"},
+		},
+		{
+			name: "Valid roles with validation",
+			claims: jwt.MapClaims{
+				"roles": []any{"admin", "user", "api"},
+			},
+			validateRoles: true,
+			expected:      []string{"admin", "user", "api"},
+		},
+		{
+			name: "Invalid roles with validation",
+			claims: jwt.MapClaims{
+				"roles": []any{"invalid_role", "fake_role"},
+			},
+			validateRoles: true,
+			expected:      []string{}, // Should filter out invalid roles
+		},
+		{
+			name:          "No roles claim",
+			claims:        jwt.MapClaims{},
+			validateRoles: false,
+			expected:      []string{},
+		},
+		{
+			name: "Non-array roles",
+			claims: jwt.MapClaims{
+				"roles": "admin",
+			},
+			validateRoles: false,
+			expected:      []string{},
+		},
+	}
+	
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := extractRolesFromClaims(tt.claims, tt.validateRoles)
+			
+			if len(result) != len(tt.expected) {
+				t.Errorf("Expected %d roles, got %d", len(tt.expected), len(result))
+				return
+			}
+			
+			for i, role := range result {
+				if i >= len(tt.expected) || role != tt.expected[i] {
+					t.Errorf("Expected role %s at position %d, got %s", tt.expected[i], i, role)
+				}
+			}
+		})
+	}
+}
+
+// TestExtractProjectsFromClaims tests project extraction from claims
+func TestExtractProjectsFromClaims(t *testing.T) {
+	tests := []struct {
+		name     string
+		claims   jwt.MapClaims
+		expected []string
+	}{
+		{
+			name: "Projects as array of interfaces",
+			claims: jwt.MapClaims{
+				"projects": []any{"project1", "project2", "project3"},
+			},
+			expected: []string{"project1", "project2", "project3"},
+		},
+		{
+			name: "Projects as string array",
+			claims: jwt.MapClaims{
+				"projects": []string{"projectA", "projectB"},
+			},
+			expected: []string{"projectA", "projectB"},
+		},
+		{
+			name:     "No projects claim",
+			claims:   jwt.MapClaims{},
+			expected: []string{},
+		},
+		{
+			name: "Mixed types in projects array",
+			claims: jwt.MapClaims{
+				"projects": []any{"project1", 123, "project2"},
+			},
+			expected: []string{"project1", "project2"}, // Should skip non-strings
+		},
+	}
+	
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := extractProjectsFromClaims(tt.claims)
+			
+			if len(result) != len(tt.expected) {
+				t.Errorf("Expected %d projects, got %d", len(tt.expected), len(result))
+				return
+			}
+			
+			for i, project := range result {
+				if i >= len(tt.expected) || project != tt.expected[i] {
+					t.Errorf("Expected project %s at position %d, got %s", tt.expected[i], i, project)
+				}
+			}
+		})
+	}
+}
+
+// TestExtractNameFromClaims tests name extraction from various formats
+func TestExtractNameFromClaims(t *testing.T) {
+	tests := []struct {
+		name     string
+		claims   jwt.MapClaims
+		expected string
+	}{
+		{
+			name: "Simple string name",
+			claims: jwt.MapClaims{
+				"name": "John Doe",
+			},
+			expected: "John Doe",
+		},
+		{
+			name: "Nested name structure",
+			claims: jwt.MapClaims{
+				"name": map[string]any{
+					"values": []any{"John", "Doe"},
+				},
+			},
+			expected: "John Doe",
+		},
+		{
+			name: "Nested name with single value",
+			claims: jwt.MapClaims{
+				"name": map[string]any{
+					"values": []any{"Alice"},
+				},
+			},
+			expected: "Alice",
+		},
+		{
+			name:     "No name claim",
+			claims:   jwt.MapClaims{},
+			expected: "",
+		},
+		{
+			name: "Empty nested values",
+			claims: jwt.MapClaims{
+				"name": map[string]any{
+					"values": []any{},
+				},
+			},
+			expected: "",
+		},
+		{
+			name: "Nested with non-string values",
+			claims: jwt.MapClaims{
+				"name": map[string]any{
+					"values": []any{123, "Smith"},
+				},
+			},
+			expected: "123 Smith", // Should convert to string
+		},
+	}
+	
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result := extractNameFromClaims(tt.claims)
+			if result != tt.expected {
+				t.Errorf("Expected '%s', got '%s'", tt.expected, result)
+			}
+		})
+	}
+}
+
+// TestGetUserFromJWT_NoValidation tests getUserFromJWT without database validation
+func TestGetUserFromJWT_NoValidation(t *testing.T) {
+	claims := jwt.MapClaims{
+		"sub":      "testuser",
+		"name":     "Test User",
+		"roles":    []any{"user", "admin"},
+		"projects": []any{"project1", "project2"},
+	}
+	
+	user, err := getUserFromJWT(claims, false, schema.AuthToken, -1)
+	
+	if err != nil {
+		t.Fatalf("Unexpected error: %v", err)
+	}
+	
+	if user.Username != "testuser" {
+		t.Errorf("Expected username 'testuser', got '%s'", user.Username)
+	}
+	
+	if user.Name != "Test User" {
+		t.Errorf("Expected name 'Test User', got '%s'", user.Name)
+	}
+	
+	if len(user.Roles) != 2 {
+		t.Errorf("Expected 2 roles, got %d", len(user.Roles))
+	}
+	
+	if len(user.Projects) != 2 {
+		t.Errorf("Expected 2 projects, got %d", len(user.Projects))
+	}
+	
+	if user.AuthType != schema.AuthToken {
+		t.Errorf("Expected AuthType %v, got %v", schema.AuthToken, user.AuthType)
+	}
+}
+
+// TestGetUserFromJWT_MissingSub tests error when sub claim is missing
+func TestGetUserFromJWT_MissingSub(t *testing.T) {
+	claims := jwt.MapClaims{
+		"name": "Test User",
+	}
+	
+	_, err := getUserFromJWT(claims, false, schema.AuthToken, -1)
+	
+	if err == nil {
+		t.Error("Expected error for missing sub claim")
+	}
+	
+	if err.Error() != "missing 'sub' claim in JWT" {
+		t.Errorf("Expected specific error message, got: %v", err)
+	}
+}
diff --git a/internal/auth/jwtSession.go b/internal/auth/jwtSession.go
index 714b986..15e5834 100644
--- a/internal/auth/jwtSession.go
+++ b/internal/auth/jwtSession.go
@@ -6,7 +6,6 @@
 package auth
 
 import (
-	"database/sql"
 	"encoding/base64"
 	"errors"
 	"fmt"
@@ -14,7 +13,6 @@ import (
 	"os"
 	"strings"
 
-	"github.com/ClusterCockpit/cc-backend/internal/repository"
 	cclog "github.com/ClusterCockpit/cc-lib/ccLogger"
 	"github.com/ClusterCockpit/cc-lib/schema"
 	"github.com/golang-jwt/jwt/v5"
@@ -77,70 +75,16 @@ func (ja *JWTSessionAuthenticator) Login(
 	}
 
 	claims := token.Claims.(jwt.MapClaims)
-	sub, _ := claims["sub"].(string)
-
-	var roles []string
-	projects := make([]string, 0)
-
-	if Keys.JwtConfig.ValidateUser {
-		var err error
-		user, err = repository.GetUserRepository().GetUser(sub)
-		if err != nil && err != sql.ErrNoRows {
-			cclog.Errorf("Error while loading user '%v'", sub)
-		}
-
-		// Deny any logins for unknown usernames
-		if user == nil {
-			cclog.Warn("Could not find user from JWT in internal database.")
-			return nil, errors.New("unknown user")
-		}
-	} else {
-		var name string
-		if wrap, ok := claims["name"].(map[string]any); ok {
-			if vals, ok := wrap["values"].([]any); ok {
-				if len(vals) != 0 {
-					name = fmt.Sprintf("%v", vals[0])
-
-					for i := 1; i < len(vals); i++ {
-						name += fmt.Sprintf(" %v", vals[i])
-					}
-				}
-			}
-		}
-
-		// Extract roles from JWT (if present)
-		if rawroles, ok := claims["roles"].([]any); ok {
-			for _, rr := range rawroles {
-				if r, ok := rr.(string); ok {
-					if schema.IsValidRole(r) {
-						roles = append(roles, r)
-					}
-				}
-			}
-		}
-
-		if rawprojs, ok := claims["projects"].([]any); ok {
-			for _, pp := range rawprojs {
-				if p, ok := pp.(string); ok {
-					projects = append(projects, p)
-				}
-			}
-		} else if rawprojs, ok := claims["projects"]; ok {
-			projects = append(projects, rawprojs.([]string)...)
-		}
-
-		user = &schema.User{
-			Username:   sub,
-			Name:       name,
-			Roles:      roles,
-			Projects:   projects,
-			AuthType:   schema.AuthSession,
-			AuthSource: schema.AuthViaToken,
-		}
-
-		if Keys.JwtConfig.SyncUserOnLogin || Keys.JwtConfig.UpdateUserOnLogin {
-			handleTokenUser(user)
-		}
+	
+	// Use shared helper to get user from JWT claims
+	user, err = getUserFromJWT(claims, Keys.JwtConfig.ValidateUser, schema.AuthSession, schema.AuthViaToken)
+	if err != nil {
+		return nil, err
+	}
+	
+	// Sync or update user if configured
+	if !Keys.JwtConfig.ValidateUser && (Keys.JwtConfig.SyncUserOnLogin || Keys.JwtConfig.UpdateUserOnLogin) {
+		handleTokenUser(user)
 	}
 
 	return user, nil
diff --git a/internal/auth/oidc.go b/internal/auth/oidc.go
index b3def70..9e36130 100644
--- a/internal/auth/oidc.go
+++ b/internal/auth/oidc.go
@@ -54,8 +54,13 @@ func setCallbackCookie(w http.ResponseWriter, r *http.Request, name, value strin
 	http.SetCookie(w, c)
 }
 
+// NewOIDC creates a new OIDC authenticator with the configured provider
 func NewOIDC(a *Authentication) *OIDC {
-	provider, err := oidc.NewProvider(context.Background(), Keys.OpenIDConfig.Provider)
+	// Use context with timeout for provider initialization
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+	
+	provider, err := oidc.NewProvider(ctx, Keys.OpenIDConfig.Provider)
 	if err != nil {
 		cclog.Fatal(err)
 	}
@@ -111,13 +116,18 @@ func (oa *OIDC) OAuth2Callback(rw http.ResponseWriter, r *http.Request) {
 		http.Error(rw, "Code not found", http.StatusBadRequest)
 		return
 	}
-	token, err := oa.client.Exchange(context.Background(), code, oauth2.VerifierOption(codeVerifier))
+	// Exchange authorization code for token with timeout
+	ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
+	defer cancel()
+	
+	token, err := oa.client.Exchange(ctx, code, oauth2.VerifierOption(codeVerifier))
 	if err != nil {
 		http.Error(rw, "Failed to exchange token: "+err.Error(), http.StatusInternalServerError)
 		return
 	}
 
-	userInfo, err := oa.provider.UserInfo(context.Background(), oauth2.StaticTokenSource(token))
+	// Get user info from OIDC provider with same timeout
+	userInfo, err := oa.provider.UserInfo(ctx, oauth2.StaticTokenSource(token))
 	if err != nil {
 		http.Error(rw, "Failed to get userinfo: "+err.Error(), http.StatusInternalServerError)
 		return
@@ -180,8 +190,8 @@ func (oa *OIDC) OAuth2Callback(rw http.ResponseWriter, r *http.Request) {
 
 	oa.authentication.SaveSession(rw, r, user)
 	cclog.Infof("login successfull: user: %#v (roles: %v, projects: %v)", user.Username, user.Roles, user.Projects)
-	ctx := context.WithValue(r.Context(), repository.ContextUserKey, user)
-	http.RedirectHandler("/", http.StatusTemporaryRedirect).ServeHTTP(rw, r.WithContext(ctx))
+	userCtx := context.WithValue(r.Context(), repository.ContextUserKey, user)
+	http.RedirectHandler("/", http.StatusTemporaryRedirect).ServeHTTP(rw, r.WithContext(userCtx))
 }
 
 func (oa *OIDC) OAuth2Login(rw http.ResponseWriter, r *http.Request) {