diff --git a/backend/internal/common/errors.go b/backend/internal/common/errors.go
index b97f2af0..9a0b41b0 100644
--- a/backend/internal/common/errors.go
+++ b/backend/internal/common/errors.go
@@ -20,7 +20,7 @@ type AlreadyInUseError struct {
 func (e *AlreadyInUseError) Error() string {
 	return e.Property + " is already in use"
 }
-func (e *AlreadyInUseError) HttpStatusCode() int { return 400 }
+func (e *AlreadyInUseError) HttpStatusCode() int { return http.StatusBadRequest }
 
 func (e *AlreadyInUseError) Is(target error) bool {
 	// Ignore the field property when checking if an error is of the type AlreadyInUseError
@@ -31,26 +31,26 @@ func (e *AlreadyInUseError) Is(target error) bool {
 type SetupAlreadyCompletedError struct{}
 
 func (e *SetupAlreadyCompletedError) Error() string       { return "setup already completed" }
-func (e *SetupAlreadyCompletedError) HttpStatusCode() int { return 400 }
+func (e *SetupAlreadyCompletedError) HttpStatusCode() int { return http.StatusConflict }
 
 type TokenInvalidOrExpiredError struct{}
 
 func (e *TokenInvalidOrExpiredError) Error() string       { return "token is invalid or expired" }
-func (e *TokenInvalidOrExpiredError) HttpStatusCode() int { return 400 }
+func (e *TokenInvalidOrExpiredError) HttpStatusCode() int { return http.StatusUnauthorized }
 
 type DeviceCodeInvalid struct{}
 
 func (e *DeviceCodeInvalid) Error() string {
 	return "one time access code must be used on the device it was generated for"
 }
-func (e *DeviceCodeInvalid) HttpStatusCode() int { return 400 }
+func (e *DeviceCodeInvalid) HttpStatusCode() int { return http.StatusUnauthorized }
 
 type TokenInvalidError struct{}
 
 func (e *TokenInvalidError) Error() string {
 	return "Token is invalid"
 }
-func (e *TokenInvalidError) HttpStatusCode() int { return 400 }
+func (e *TokenInvalidError) HttpStatusCode() int { return http.StatusUnauthorized }
 
 type OidcMissingAuthorizationError struct{}
 
@@ -60,46 +60,51 @@ func (e *OidcMissingAuthorizationError) HttpStatusCode() int { return http.Statu
 type OidcGrantTypeNotSupportedError struct{}
 
 func (e *OidcGrantTypeNotSupportedError) Error() string       { return "grant type not supported" }
-func (e *OidcGrantTypeNotSupportedError) HttpStatusCode() int { return 400 }
+func (e *OidcGrantTypeNotSupportedError) HttpStatusCode() int { return http.StatusBadRequest }
 
 type OidcMissingClientCredentialsError struct{}
 
 func (e *OidcMissingClientCredentialsError) Error() string       { return "client id or secret not provided" }
-func (e *OidcMissingClientCredentialsError) HttpStatusCode() int { return 400 }
+func (e *OidcMissingClientCredentialsError) HttpStatusCode() int { return http.StatusBadRequest }
 
 type OidcClientSecretInvalidError struct{}
 
 func (e *OidcClientSecretInvalidError) Error() string       { return "invalid client secret" }
-func (e *OidcClientSecretInvalidError) HttpStatusCode() int { return 400 }
+func (e *OidcClientSecretInvalidError) HttpStatusCode() int { return http.StatusUnauthorized }
 
 type OidcClientAssertionInvalidError struct{}
 
 func (e *OidcClientAssertionInvalidError) Error() string       { return "invalid client assertion" }
-func (e *OidcClientAssertionInvalidError) HttpStatusCode() int { return 400 }
+func (e *OidcClientAssertionInvalidError) HttpStatusCode() int { return http.StatusUnauthorized }
 
 type OidcInvalidAuthorizationCodeError struct{}
 
 func (e *OidcInvalidAuthorizationCodeError) Error() string       { return "invalid authorization code" }
-func (e *OidcInvalidAuthorizationCodeError) HttpStatusCode() int { return 400 }
+func (e *OidcInvalidAuthorizationCodeError) HttpStatusCode() int { return http.StatusBadRequest }
+
+type OidcClientNotFoundError struct{}
+
+func (e *OidcClientNotFoundError) Error() string       { return "client not found" }
+func (e *OidcClientNotFoundError) HttpStatusCode() int { return http.StatusNotFound }
 
 type OidcMissingCallbackURLError struct{}
 
 func (e *OidcMissingCallbackURLError) Error() string {
 	return "unable to detect callback url, it might be necessary for an admin to fix this"
 }
-func (e *OidcMissingCallbackURLError) HttpStatusCode() int { return 400 }
+func (e *OidcMissingCallbackURLError) HttpStatusCode() int { return http.StatusBadRequest }
 
 type OidcInvalidCallbackURLError struct{}
 
 func (e *OidcInvalidCallbackURLError) Error() string {
 	return "invalid callback URL, it might be necessary for an admin to fix this"
 }
-func (e *OidcInvalidCallbackURLError) HttpStatusCode() int { return 400 }
+func (e *OidcInvalidCallbackURLError) HttpStatusCode() int { return http.StatusBadRequest }
 
 type FileTypeNotSupportedError struct{}
 
 func (e *FileTypeNotSupportedError) Error() string       { return "file type not supported" }
-func (e *FileTypeNotSupportedError) HttpStatusCode() int { return 400 }
+func (e *FileTypeNotSupportedError) HttpStatusCode() int { return http.StatusBadRequest }
 
 type FileTooLargeError struct {
 	MaxSize string
diff --git a/backend/internal/controller/oidc_controller.go b/backend/internal/controller/oidc_controller.go
index 5dd9404f..193a6723 100644
--- a/backend/internal/controller/oidc_controller.go
+++ b/backend/internal/controller/oidc_controller.go
@@ -335,11 +335,13 @@ func (oc *OidcController) introspectTokenHandler(c *gin.Context) {
 	)
 	creds.ClientID, creds.ClientSecret, ok = utils.OAuthClientBasicAuth(c.Request)
 	if !ok {
-		// If there's no basic auth, check if we have a bearer token
+		// If there's no basic auth, check if we have a bearer token (used as client assertion)
 		bearer, ok := utils.BearerAuth(c.Request)
 		if ok {
 			creds.ClientAssertionType = service.ClientAssertionTypeJWTBearer
 			creds.ClientAssertion = bearer
+			// When using client assertions, client_id can be passed as a form field
+			creds.ClientID = input.ClientID
 		}
 	}
 
@@ -662,8 +664,13 @@ func (oc *OidcController) updateAllowedUserGroupsHandler(c *gin.Context) {
 }
 
 func (oc *OidcController) deviceAuthorizationHandler(c *gin.Context) {
+	// Per RFC 8628 (OAuth 2.0 Device Authorization Grant), parameters for the device authorization request MUST be sent in the body of the POST request
+	// Gin's "ShouldBind" by default reads from the query string too, so we need to reset all query string args before invoking ShouldBind
+	c.Request.URL.RawQuery = ""
+
 	var input dto.OidcDeviceAuthorizationRequestDto
-	if err := c.ShouldBind(&input); err != nil {
+	err := c.ShouldBind(&input)
+	if err != nil {
 		_ = c.Error(err)
 		return
 	}
diff --git a/backend/internal/dto/oidc_dto.go b/backend/internal/dto/oidc_dto.go
index 08e271bb..e6a186a6 100644
--- a/backend/internal/dto/oidc_dto.go
+++ b/backend/internal/dto/oidc_dto.go
@@ -98,7 +98,8 @@ type OidcCreateTokensDto struct {
 }
 
 type OidcIntrospectDto struct {
-	Token string `form:"token" binding:"required"`
+	Token    string `form:"token" binding:"required"`
+	ClientID string `form:"client_id"`
 }
 
 type OidcUpdateAllowedUserGroupsDto struct {
diff --git a/backend/internal/service/oidc_service.go b/backend/internal/service/oidc_service.go
index 828e0710..1d04c8d1 100644
--- a/backend/internal/service/oidc_service.go
+++ b/backend/internal/service/oidc_service.go
@@ -1644,34 +1644,19 @@ func clientAuthCredentialsFromCreateTokensDto(d *dto.OidcCreateTokensDto) Client
 }
 
 func (s *OidcService) verifyClientCredentialsInternal(ctx context.Context, tx *gorm.DB, input ClientAuthCredentials, allowPublicClientsWithoutAuth bool) (client *model.OidcClient, err error) {
-	isClientAssertion := input.ClientAssertionType == ClientAssertionTypeJWTBearer && input.ClientAssertion != ""
-
-	// Determine the client ID based on the authentication method
-	var clientID string
-	switch {
-	case isClientAssertion:
-		// Extract client ID from the JWT assertion's 'sub' claim
-		clientID, err = s.extractClientIDFromAssertion(input.ClientAssertion)
-		if err != nil {
-			slog.Error("Failed to extract client ID from assertion", "error", err)
-			return nil, &common.OidcClientAssertionInvalidError{}
-		}
-	case input.ClientID != "":
-		// Use the provided client ID for other authentication methods
-		clientID = input.ClientID
-	default:
+	if input.ClientID == "" {
 		return nil, &common.OidcMissingClientCredentialsError{}
 	}
 
 	// Load the OIDC client's configuration
 	err = tx.
 		WithContext(ctx).
-		First(&client, "id = ?", clientID).
+		First(&client, "id = ?", input.ClientID).
 		Error
-	if err != nil {
-		if errors.Is(err, gorm.ErrRecordNotFound) && isClientAssertion {
-			return nil, &common.OidcClientAssertionInvalidError{}
-		}
+	if errors.Is(err, gorm.ErrRecordNotFound) {
+		slog.WarnContext(ctx, "Client not found", slog.String("client", input.ClientID))
+		return nil, &common.OidcClientNotFoundError{}
+	} else if err != nil {
 		return nil, err
 	}
 
@@ -1686,7 +1671,7 @@ func (s *OidcService) verifyClientCredentialsInternal(ctx context.Context, tx *g
 		return client, nil
 
 	// Next, check if we want to use client assertions from federated identities
-	case isClientAssertion:
+	case input.ClientAssertionType == ClientAssertionTypeJWTBearer && input.ClientAssertion != "":
 		err = s.verifyClientAssertionFromFederatedIdentities(ctx, client, input)
 		if err != nil {
 			slog.WarnContext(ctx, "Invalid assertion for client", slog.String("client", client.ID), slog.Any("error", err))
@@ -1783,36 +1768,20 @@ func (s *OidcService) verifyClientAssertionFromFederatedIdentities(ctx context.C
 	// (Note: we don't use jwt.WithIssuer() because that would be redundant)
 	_, err = jwt.Parse(assertion,
 		jwt.WithValidate(true),
+
 		jwt.WithAcceptableSkew(clockSkew),
 		jwt.WithKeySet(jwks, jws.WithInferAlgorithmFromKey(true), jws.WithUseDefault(true)),
 		jwt.WithAudience(audience),
 		jwt.WithSubject(subject),
 	)
 	if err != nil {
-		return fmt.Errorf("client assertion is not valid: %w", err)
+		return fmt.Errorf("client assertion could not be verified: %w", err)
 	}
 
 	// If we're here, the assertion is valid
 	return nil
 }
 
-// extractClientIDFromAssertion extracts the client_id from the JWT assertion's 'sub' claim
-func (s *OidcService) extractClientIDFromAssertion(assertion string) (string, error) {
-	// Parse the JWT without verification first to get the claims
-	insecureToken, err := jwt.ParseInsecure([]byte(assertion))
-	if err != nil {
-		return "", fmt.Errorf("failed to parse JWT assertion: %w", err)
-	}
-
-	// Extract the subject claim which must be the client_id according to RFC 7523
-	sub, ok := insecureToken.Subject()
-	if !ok || sub == "" {
-		return "", fmt.Errorf("missing or invalid 'sub' claim in JWT assertion")
-	}
-
-	return sub, nil
-}
-
 func (s *OidcService) GetClientPreview(ctx context.Context, clientID string, userID string, scopes []string) (*dto.OidcClientPreviewDto, error) {
 	tx := s.db.Begin()
 	defer func() {
diff --git a/backend/internal/service/oidc_service_test.go b/backend/internal/service/oidc_service_test.go
index 4dbab3f6..4374a430 100644
--- a/backend/internal/service/oidc_service_test.go
+++ b/backend/internal/service/oidc_service_test.go
@@ -229,6 +229,12 @@ func TestOidcService_verifyClientCredentialsInternal(t *testing.T) {
 					Subject:  federatedClient.ID,
 					JWKS:     federatedClientIssuer + "/jwks.json",
 				},
+				{
+					Issuer:   "federated-issuer-2",
+					Audience: federatedClientAudience,
+					Subject:  "my-federated-client",
+					JWKS:     federatedClientIssuer + "/jwks.json",
+				},
 				{Issuer: federatedClientIssuerDefaults},
 			},
 		},
@@ -461,6 +467,43 @@ func TestOidcService_verifyClientCredentialsInternal(t *testing.T) {
 
 				// Generate a token
 				input := dto.OidcCreateTokensDto{
+					ClientID:            federatedClient.ID,
+					ClientAssertion:     string(signedToken),
+					ClientAssertionType: ClientAssertionTypeJWTBearer,
+				}
+				createdToken, err := s.createTokenFromClientCredentials(t.Context(), input)
+				require.NoError(t, err)
+				require.NotNil(t, token)
+
+				// Verify the token
+				claims, err := s.jwtService.VerifyOAuthAccessToken(createdToken.AccessToken)
+				require.NoError(t, err, "Failed to verify generated token")
+
+				// Check the claims
+				subject, ok := claims.Subject()
+				_ = assert.True(t, ok, "User ID not found in token") &&
+					assert.Equal(t, "client-"+federatedClient.ID, subject, "Token subject should match federated client ID with prefix")
+				audience, ok := claims.Audience()
+				_ = assert.True(t, ok, "Audience not found in token") &&
+					assert.Equal(t, []string{federatedClient.ID}, audience, "Audience should contain the federated client ID")
+			})
+
+			t.Run("Succeeds with valid assertion and custom subject", func(t *testing.T) {
+				// Create JWT for federated identity
+				token, err := jwt.NewBuilder().
+					Issuer("federated-issuer-2").
+					Audience([]string{federatedClientAudience}).
+					Subject("my-federated-client").
+					IssuedAt(time.Now()).
+					Expiration(time.Now().Add(10 * time.Minute)).
+					Build()
+				require.NoError(t, err)
+				signedToken, err := jwt.Sign(token, jwt.WithKey(jwa.ES256(), privateJWK))
+				require.NoError(t, err)
+
+				// Generate a token
+				input := dto.OidcCreateTokensDto{
+					ClientID:            federatedClient.ID,
 					ClientAssertion:     string(signedToken),
 					ClientAssertionType: ClientAssertionTypeJWTBearer,
 				}
@@ -483,6 +526,7 @@ func TestOidcService_verifyClientCredentialsInternal(t *testing.T) {
 
 			t.Run("Fails with invalid assertion", func(t *testing.T) {
 				input := dto.OidcCreateTokensDto{
+					ClientID:            confidentialClient.ID,
 					ClientAssertion:     "invalid.jwt.token",
 					ClientAssertionType: ClientAssertionTypeJWTBearer,
 				}
diff --git a/frontend/messages/cs.json b/frontend/messages/cs.json
index 0368fb55..8bf78ad7 100644
--- a/frontend/messages/cs.json
+++ b/frontend/messages/cs.json
@@ -365,7 +365,6 @@
 	"enter_code_displayed_in_previous_step": "Zadejte kód, který byl zobrazen v předchozím kroku.",
 	"authorize": "Autorizovat",
 	"federated_client_credentials": "Údaje o klientovi ve federaci",
-	"federated_client_credentials_description": "Pomocí federovaných přihlašovacích údajů klienta můžete ověřit klienty OIDC pomocí JWT tokenů vydaných třetí stranou.",
 	"add_federated_client_credential": "Přidat údaje federovaného klienta",
 	"add_another_federated_client_credential": "Přidat dalšího federovaného klienta",
 	"oidc_allowed_group_count": "Počet povolených skupin",
diff --git a/frontend/messages/da.json b/frontend/messages/da.json
index 9afdca79..5d2b3336 100644
--- a/frontend/messages/da.json
+++ b/frontend/messages/da.json
@@ -365,7 +365,6 @@
 	"enter_code_displayed_in_previous_step": "Indtast koden, der blev vist i det forrige trin.",
 	"authorize": "Godkend",
 	"federated_client_credentials": "Federated klientlegitimationsoplysninger",
-	"federated_client_credentials_description": "Ved hjælp af federated klientlegitimationsoplysninger kan du godkende OIDC-klienter med JWT-tokens udstedt af tredjepartsudbydere.",
 	"add_federated_client_credential": "Tilføj federated klientlegitimation",
 	"add_another_federated_client_credential": "Tilføj endnu en federated klientlegitimation",
 	"oidc_allowed_group_count": "Tilladt antal grupper",
diff --git a/frontend/messages/de.json b/frontend/messages/de.json
index bffc38c6..79885fcc 100644
--- a/frontend/messages/de.json
+++ b/frontend/messages/de.json
@@ -365,7 +365,6 @@
 	"enter_code_displayed_in_previous_step": "Gib den Code ein, der im vorherigen Schritt angezeigt wurde.",
 	"authorize": "Autorisieren",
 	"federated_client_credentials": "Federated Client Credentials",
-	"federated_client_credentials_description": "Mit Hilfe von Verbund-Client-Anmeldeinformationen kannst du OIDC-Clients mit JWT-Tokens authentifizieren, die von Drittanbietern ausgestellt wurden.",
 	"add_federated_client_credential": "Föderierte Client-Anmeldeinfos hinzufügen",
 	"add_another_federated_client_credential": "Weitere Anmeldeinformationen für einen Verbundclient hinzufügen",
 	"oidc_allowed_group_count": "Erlaubte Gruppenanzahl",
diff --git a/frontend/messages/en.json b/frontend/messages/en.json
index e328330e..e89938b8 100644
--- a/frontend/messages/en.json
+++ b/frontend/messages/en.json
@@ -365,7 +365,7 @@
 	"enter_code_displayed_in_previous_step": "Enter the code that was displayed in the previous step.",
 	"authorize": "Authorize",
 	"federated_client_credentials": "Federated Client Credentials",
-	"federated_client_credentials_description": "Using federated client credentials, you can authenticate OIDC clients using JWT tokens issued by third-party authorities.",
+	"federated_client_credentials_description": "Federated client credentials allow authenticating OIDC clients without managing long-lived secrets. They leverage JWT tokens issued by third-party authorities for client assertions, e.g. workload identity tokens.",
 	"add_federated_client_credential": "Add Federated Client Credential",
 	"add_another_federated_client_credential": "Add another federated client credential",
 	"oidc_allowed_group_count": "Allowed Group Count",
diff --git a/frontend/messages/es.json b/frontend/messages/es.json
index 9c1cce93..ac6fdd78 100644
--- a/frontend/messages/es.json
+++ b/frontend/messages/es.json
@@ -365,7 +365,6 @@
 	"enter_code_displayed_in_previous_step": "Introduce el código que se mostró en el paso anterior.",
 	"authorize": "Autorizar",
 	"federated_client_credentials": "Credenciales de cliente federadas",
-	"federated_client_credentials_description": "Mediante credenciales de cliente federadas, puedes autenticar clientes OIDC utilizando tokens JWT emitidos por autoridades de terceros.",
 	"add_federated_client_credential": "Añadir credenciales de cliente federado",
 	"add_another_federated_client_credential": "Añadir otra credencial de cliente federado",
 	"oidc_allowed_group_count": "Recuento de grupos permitidos",
diff --git a/frontend/messages/et.json b/frontend/messages/et.json
index e328330e..d3aedc7c 100644
--- a/frontend/messages/et.json
+++ b/frontend/messages/et.json
@@ -365,7 +365,6 @@
 	"enter_code_displayed_in_previous_step": "Enter the code that was displayed in the previous step.",
 	"authorize": "Authorize",
 	"federated_client_credentials": "Federated Client Credentials",
-	"federated_client_credentials_description": "Using federated client credentials, you can authenticate OIDC clients using JWT tokens issued by third-party authorities.",
 	"add_federated_client_credential": "Add Federated Client Credential",
 	"add_another_federated_client_credential": "Add another federated client credential",
 	"oidc_allowed_group_count": "Allowed Group Count",
diff --git a/frontend/messages/fi.json b/frontend/messages/fi.json
index b8ba5899..59d1f041 100644
--- a/frontend/messages/fi.json
+++ b/frontend/messages/fi.json
@@ -365,7 +365,6 @@
 	"enter_code_displayed_in_previous_step": "Syötä edellisessä vaiheessa näkynyt koodi.",
 	"authorize": "Salli",
 	"federated_client_credentials": "Federoidut asiakastunnukset",
-	"federated_client_credentials_description": "Yhdistettyjen asiakastunnistetietojen avulla voit todentaa OIDC-asiakkaat kolmannen osapuolen myöntämillä JWT-tunnuksilla.",
 	"add_federated_client_credential": "Lisää federoitu asiakastunnus",
 	"add_another_federated_client_credential": "Lisää toinen federoitu asiakastunnus",
 	"oidc_allowed_group_count": "Sallittujen ryhmien määrä",
diff --git a/frontend/messages/fr.json b/frontend/messages/fr.json
index aa9f71b2..9ff785d4 100644
--- a/frontend/messages/fr.json
+++ b/frontend/messages/fr.json
@@ -365,7 +365,6 @@
 	"enter_code_displayed_in_previous_step": "Entrez le code affiché à l'étape précédente.",
 	"authorize": "Autoriser",
 	"federated_client_credentials": "Identifiants client fédérés",
-	"federated_client_credentials_description": "Avec des identifiants clients fédérés, vous pouvez authentifier des clients OIDC avec des tokens JWT émis par des autorités tierces.",
 	"add_federated_client_credential": "Ajouter un identifiant client fédéré",
 	"add_another_federated_client_credential": "Ajouter un autre identifiant client fédéré",
 	"oidc_allowed_group_count": "Nombre de groupes autorisés",
diff --git a/frontend/messages/it.json b/frontend/messages/it.json
index 890ad08c..e4337b43 100644
--- a/frontend/messages/it.json
+++ b/frontend/messages/it.json
@@ -365,7 +365,6 @@
 	"enter_code_displayed_in_previous_step": "Inserisci il codice visualizzato nel passaggio precedente.",
 	"authorize": "Autorizza",
 	"federated_client_credentials": "Identità Federate",
-	"federated_client_credentials_description": "Utilizzando identità federate, è possibile autenticare i client OIDC utilizzando i token JWT emessi da autorità di terze parti.",
 	"add_federated_client_credential": "Aggiungi Identità Federata",
 	"add_another_federated_client_credential": "Aggiungi un'altra identità federata",
 	"oidc_allowed_group_count": "Numero Gruppi Consentiti",
diff --git a/frontend/messages/ja.json b/frontend/messages/ja.json
index fa8c024c..2f480471 100644
--- a/frontend/messages/ja.json
+++ b/frontend/messages/ja.json
@@ -365,7 +365,6 @@
 	"enter_code_displayed_in_previous_step": "前のステップで表示されたコードを入力してください。",
 	"authorize": "Authorize",
 	"federated_client_credentials": "連携クライアントの資格情報",
-	"federated_client_credentials_description": "Using federated client credentials, you can authenticate OIDC clients using JWT tokens issued by third-party authorities.",
 	"add_federated_client_credential": "Add Federated Client Credential",
 	"add_another_federated_client_credential": "Add another federated client credential",
 	"oidc_allowed_group_count": "許可されたグループ数",
diff --git a/frontend/messages/ko.json b/frontend/messages/ko.json
index 0de41375..6ec07029 100644
--- a/frontend/messages/ko.json
+++ b/frontend/messages/ko.json
@@ -365,7 +365,6 @@
 	"enter_code_displayed_in_previous_step": "이전 단계에 표시된 코드를 입력하세요.",
 	"authorize": "승인",
 	"federated_client_credentials": "연동 클라이언트 자격 증명",
-	"federated_client_credentials_description": "연동 클라이언트 자격 증명을 이용하여, OIDC 클라이언트를 제3자 인증 기관에서 발급한 JWT 토큰을 이용해 인증할 수 있습니다.",
 	"add_federated_client_credential": "연동 클라이언트 자격 증명 추가",
 	"add_another_federated_client_credential": "다른 연동 클라이언트 자격 증명 추가",
 	"oidc_allowed_group_count": "허용된 그룹 수",
diff --git a/frontend/messages/nl.json b/frontend/messages/nl.json
index 19cb99d3..958da44c 100644
--- a/frontend/messages/nl.json
+++ b/frontend/messages/nl.json
@@ -365,7 +365,6 @@
 	"enter_code_displayed_in_previous_step": "Voer de code in die in de vorige stap werd getoond.",
 	"authorize": "Autoriseren",
 	"federated_client_credentials": "Federatieve clientreferenties",
-	"federated_client_credentials_description": "Met federatieve clientreferenties kun je OIDC-clients verifiëren met JWT-tokens die zijn uitgegeven door andere instanties.",
 	"add_federated_client_credential": "Federatieve clientreferenties toevoegen",
 	"add_another_federated_client_credential": "Voeg nog een federatieve clientreferentie toe",
 	"oidc_allowed_group_count": "Aantal groepen met toegang",
diff --git a/frontend/messages/no.json b/frontend/messages/no.json
index 1c131f38..320291e5 100644
--- a/frontend/messages/no.json
+++ b/frontend/messages/no.json
@@ -365,7 +365,6 @@
 	"enter_code_displayed_in_previous_step": "Enter the code that was displayed in the previous step.",
 	"authorize": "Authorize",
 	"federated_client_credentials": "Federated Client Credentials",
-	"federated_client_credentials_description": "Using federated client credentials, you can authenticate OIDC clients using JWT tokens issued by third-party authorities.",
 	"add_federated_client_credential": "Add Federated Client Credential",
 	"add_another_federated_client_credential": "Add another federated client credential",
 	"oidc_allowed_group_count": "Allowed Group Count",
diff --git a/frontend/messages/pl.json b/frontend/messages/pl.json
index ee6a0148..be63509c 100644
--- a/frontend/messages/pl.json
+++ b/frontend/messages/pl.json
@@ -365,7 +365,6 @@
 	"enter_code_displayed_in_previous_step": "Wprowadź kod wyświetlony w poprzednim kroku.",
 	"authorize": "Autoryzuj",
 	"federated_client_credentials": "Połączone poświadczenia klienta",
-	"federated_client_credentials_description": "Korzystając z połączonych poświadczeń klienta, możecie uwierzytelnić klientów OIDC za pomocą tokenów JWT wydanych przez zewnętrzne organy.",
 	"add_federated_client_credential": "Dodaj poświadczenia klienta federacyjnego",
 	"add_another_federated_client_credential": "Dodaj kolejne poświadczenia klienta federacyjnego",
 	"oidc_allowed_group_count": "Dopuszczalna liczba grup",
diff --git a/frontend/messages/pt-BR.json b/frontend/messages/pt-BR.json
index 1b94665b..3d28baec 100644
--- a/frontend/messages/pt-BR.json
+++ b/frontend/messages/pt-BR.json
@@ -365,7 +365,6 @@
 	"enter_code_displayed_in_previous_step": "Digite o código que apareceu na etapa anterior.",
 	"authorize": "Autorizar",
 	"federated_client_credentials": "Credenciais de Cliente Federadas",
-	"federated_client_credentials_description": "Ao utilizar credenciais de cliente federadas, é possível autenticar clientes OIDC usando tokens JWT emitidos por autoridades de terceiros.",
 	"add_federated_client_credential": "Adicionar credencial de cliente federado",
 	"add_another_federated_client_credential": "Adicionar outra credencial de cliente federado",
 	"oidc_allowed_group_count": "Total de grupos permitidos",
diff --git a/frontend/messages/ru.json b/frontend/messages/ru.json
index 3f2239fa..7774a94e 100644
--- a/frontend/messages/ru.json
+++ b/frontend/messages/ru.json
@@ -365,7 +365,6 @@
 	"enter_code_displayed_in_previous_step": "Введите код, который был отображен на предыдущем шаге.",
 	"authorize": "Авторизовать",
 	"federated_client_credentials": "Федеративные учетные данные клиента",
-	"federated_client_credentials_description": "Используя федеративные учетные данные клиента, вы можете аутентифицировать клиентов OIDC с помощью токенов JWT, выпущенных сторонними поставщиками удостоверений.",
 	"add_federated_client_credential": "Добавить федеративные учетные данные клиента",
 	"add_another_federated_client_credential": "Добавить другие федеративные учетные данные клиента",
 	"oidc_allowed_group_count": "Число разрешенных групп",
diff --git a/frontend/messages/sv.json b/frontend/messages/sv.json
index c45fdf43..2a46b86f 100644
--- a/frontend/messages/sv.json
+++ b/frontend/messages/sv.json
@@ -365,7 +365,6 @@
 	"enter_code_displayed_in_previous_step": "Ange koden som visades i föregående steg.",
 	"authorize": "Godkänn",
 	"federated_client_credentials": "Federerade klientuppgifter",
-	"federated_client_credentials_description": "Med hjälp av federerade klientuppgifter kan du autentisera OIDC-klienter med JWT-tokens som utfärdats av externa auktoriteter.",
 	"add_federated_client_credential": "Lägg till federerad klientuppgift",
 	"add_another_federated_client_credential": "Lägg till ytterligare en federerad klientuppgift",
 	"oidc_allowed_group_count": "Tillåtet antal grupper",
diff --git a/frontend/messages/tr.json b/frontend/messages/tr.json
index dc7b5985..608939db 100644
--- a/frontend/messages/tr.json
+++ b/frontend/messages/tr.json
@@ -365,7 +365,6 @@
 	"enter_code_displayed_in_previous_step": "Önceki adımda görüntülenen kodu girin.",
 	"authorize": "Yetkilendir",
 	"federated_client_credentials": "Birleştirilmiş İstemci Kimlik Bilgileri",
-	"federated_client_credentials_description": "Birleşik istemci kimlik bilgilerini kullanarak, üçüncü taraf otoriteleri tarafından verilen JWT token'ları kullanarak OIDC istemcilerinin kimliklerini doğrulayabilirsiniz.",
 	"add_federated_client_credential": "Birleştirilmiş İstemci Kimlik Bilgisi Ekle",
 	"add_another_federated_client_credential": "Başka bir birleştirilmiş istemci kimlik bilgisi ekle",
 	"oidc_allowed_group_count": "İzin Verilen Grup Sayısı",
diff --git a/frontend/messages/uk.json b/frontend/messages/uk.json
index c4e7955c..06b548fe 100644
--- a/frontend/messages/uk.json
+++ b/frontend/messages/uk.json
@@ -365,7 +365,6 @@
 	"enter_code_displayed_in_previous_step": "Введіть код, який було показано на попередньому кроці.",
 	"authorize": "Авторизувати",
 	"federated_client_credentials": "Федеративні облікові дані клієнта",
-	"federated_client_credentials_description": "За допомогою федеративних облікових даних клієнта ви можете автентифікувати клієнтів OIDC за допомогою токенів JWT, виданих третіми сторонами.",
 	"add_federated_client_credential": "Додати федеративний обліковий запис клієнта",
 	"add_another_federated_client_credential": "Додати ще один федеративний обліковий запис клієнта",
 	"oidc_allowed_group_count": "Кількість дозволених груп",
diff --git a/frontend/messages/vi.json b/frontend/messages/vi.json
index 611a887c..8d861e5a 100644
--- a/frontend/messages/vi.json
+++ b/frontend/messages/vi.json
@@ -365,7 +365,6 @@
 	"enter_code_displayed_in_previous_step": "Nhập mã đã hiển thị ở bước trước.",
 	"authorize": "Cho phép",
 	"federated_client_credentials": "Thông Tin Xác Thực Của Federated Clients",
-	"federated_client_credentials_description": "Sử dụng thông tin xác thực của federated client, bạn có thể xác thực các client OIDC bằng cách sử dụng token JWT được cấp bởi các bên thứ ba.",
 	"add_federated_client_credential": "Thêm thông tin xác thực cho federated clients",
 	"add_another_federated_client_credential": "Thêm một thông tin xác thực cho federated clients khác",
 	"oidc_allowed_group_count": "Số lượng nhóm được phép",
diff --git a/frontend/messages/zh-CN.json b/frontend/messages/zh-CN.json
index 5b051731..99b9a987 100644
--- a/frontend/messages/zh-CN.json
+++ b/frontend/messages/zh-CN.json
@@ -365,7 +365,6 @@
 	"enter_code_displayed_in_previous_step": "输入在上一步中显示的代码",
 	"authorize": "授权",
 	"federated_client_credentials": "联合身份",
-	"federated_client_credentials_description": "您可以使用联合身份，通过第三方授权机构签发的 JWT 令牌，对 OIDC 客户端进行认证。",
 	"add_federated_client_credential": "添加联合身份",
 	"add_another_federated_client_credential": "再添加一个联合身份",
 	"oidc_allowed_group_count": "允许的群组数量",
diff --git a/frontend/messages/zh-TW.json b/frontend/messages/zh-TW.json
index 58c57e5a..eac55e18 100644
--- a/frontend/messages/zh-TW.json
+++ b/frontend/messages/zh-TW.json
@@ -365,7 +365,6 @@
 	"enter_code_displayed_in_previous_step": "請輸入上一步顯示的代碼。",
 	"authorize": "授權",
 	"federated_client_credentials": "聯邦身分",
-	"federated_client_credentials_description": "使用聯邦身分，您可以透過由第三方授權機構簽發的 JWT 令牌來驗證 OIDC 客戶端。",
 	"add_federated_client_credential": "增加聯邦身分",
 	"add_another_federated_client_credential": "新增另一組聯邦身分",
 	"oidc_allowed_group_count": "允許的群組數量",
diff --git a/tests/specs/oidc.spec.ts b/tests/specs/oidc.spec.ts
index 9f16d8fc..2b96709f 100644
--- a/tests/specs/oidc.spec.ts
+++ b/tests/specs/oidc.spec.ts
@@ -332,6 +332,7 @@ test.describe('Introspection endpoint', () => {
 				Authorization: 'Bearer ' + clientAssertion
 			},
 			form: {
+				client_id: oidcClients.federated.id,
 				token: validAccessToken
 			}
 		});
@@ -374,6 +375,7 @@ test.describe('Introspection endpoint', () => {
 				Authorization: 'Bearer ' + clientAssertion
 			},
 			form: {
+				client_id: oidcClients.federated.id,
 				token: validAccessToken
 			}
 		});