A flaw was found in the org.keycloak.services package of Keycloak. When an authentication flow is initiated through the login-actions/reset-credentials entry point, the resulting authorization session fails to evaluate and apply client-level mandatory PKCE settings. If a user subsequently navigates back to the standard login form and completes authentication, Keycloak issues an authorization code that lacks associated code challenge metadata. Because the token endpoint validates PKCE based on the presence of metadata in the code rather than the client configuration, the code can be redeemed for tokens without a codeverifier. An attacker who intercepts this authorization code can perform a code injection attack to obtain access and refresh tokens, allowing them to impersonate the victim and access or modify protected data.

A flaw was found in the client registration component of Keycloak, an open-source identity and access management solution. When a vault provider is used to store sensitive information, an authenticated client owner can use a specially crafted reference to trick the system into revealing secrets. By updating a client secret to point to a vault entry and then requesting the client configuration, the owner can see the secret value in plain text. This could lead to the exposure of sensitive credentials that the user should not be able to access.

A vulnerability was found in Keycloak where the JWT Authorization Grant (RFC 7523) fails to enforce login restrictions configured on OIDC or Google identity providers. Specifically, restrictions such as Filtered by claims or Hosted Domain are bypassed when the grant is processed. An authenticated confidential client with the JWT Authorization Grant enabled can submit a signed assertion for an existing federated user and receive realm tokens, even if the assertion contains claims that violate the identity provider's security policies. An attacker with client credentials and a validly signed assertion can bypass intended access controls to obtain unauthorized realm access for federated users.

A CPU-based Denial of Service vulnerability was found in Keycloak within the org.keycloak.saml component. The flaw exists in the way SAML XML dateTime and duration strings are parsed. When an XML document containing an excessively long string for these specific types is processed, the parser enters a resource-intensive state, consuming significant CPU cycles. An unauthenticated remote attacker can exploit this by sending crafted SAML XML payloads via HTTP POST to endpoints such as /realms/{realm}/protocol/saml, /realms/{realm}/broker/saml/endpoint, or /realms/{realm}/protocol/saml/resolve. Successful exploitation does not require valid client registration, credentials, or valid SAML signatures. The concrete impact is a sustained high CPU load on the Keycloak server, leading to service unresponsiveness and a total denial of service for authentication and authorization flows.

A CPU-based Denial of Service vulnerability was found in Keycloak within the org.keycloak.saml component. The flaw exists in the way SAML XML dateTime and duration strings are parsed. When an XML document containing an excessively long string for these specific types is processed, the parser enters a resource-intensive state, consuming significant CPU cycles. An unauthenticated remote attacker can exploit this by sending crafted SAML XML payloads via HTTP POST to endpoints such as /realms/{realm}/protocol/saml, /realms/{realm}/broker/saml/endpoint, or /realms/{realm}/protocol/saml/resolve. Successful exploitation does not require valid client registration, credentials, or valid SAML signatures. The concrete impact is a sustained high CPU load on the Keycloak server, leading to service unresponsiveness and a total denial of service for authentication and authorization flows.

A flaw was found in the org.keycloak.protocol.oidc package of Keycloak. The OAuth 2.0 Device Authorization Grant flow does not correctly enforce the per-client minimum.acr.value setting. While the standard Authorization Code flow properly requires multi-factor authentication (MFA) when this setting is present, the Device Authorization flow allows authentication to complete at a lower Level of Assurance (LoA 1, password only). The root cause is a missing validation step in the device grant code path to ensure the resulting authentication context class reference (ACR) meets the client's configured minimum. An attacker with knowledge of a user's primary credentials can exploit this to bypass MFA requirements. Successful exploitation allows the attacker to obtain a valid access token with the client's scoped roles and use it to perform unauthorized actions via the Keycloak Admin REST API, such as managing users or modifying realm configurations.

A Blind Server-Side Request Forgery (SSRF) vulnerability was discovered in Keycloak within the org.keycloak.services.x509 component. When the X.509 client-certificate authenticator is enabled with CRL Distribution Point (CRLDP) or OCSP revocation checking, Keycloak attempts to fetch the CRL and OCSP responder URLs embedded in the presented client certificate before performing trust revalidation. An unauthenticated attacker can exploit this by presenting a crafted certificate containing attacker-controlled URLs in the CRL-DP or OCSP Authority Information Access (AIA) extensions. This induces the Keycloak server to initiate outbound HTTP GET or POST requests to arbitrary internal or external endpoints. A secondary exploitation vector exists when a proxy-header cert-lookup provider is configured with proxy-trusted-addresses unset, allowing the attack to be performed via plain HTTP headers without a valid TLS connection. Successful exploitation allows an attacker to probe internal network resources or interact with internal services that are otherwise unreachable from the outside.

A flaw was found in the Micrometer user-event metrics listener of Keycloak, a solution for integrated identity and access management. The issue occurs when the listener is configured to include the idp tag. An unauthenticated attacker can send requests to the identity broker login endpoint using arbitrary provider aliases, causing the system to create an unlimited number of metric time series. This can lead to excessive memory consumption and degrade the performance of both the server and its monitoring tools.

A flaw was found in Keycloak's Account REST API session binding mechanism. The issue exists because the sid session ID claim is not included in the blocked claim list for Dynamic Client Registration DCR protocol mappers. A malicious DCR client owner can configure mappers to substitute the azp authorized party and sid claims in their access token with values derived from user-controlled profile fields. When the Account REST API processes this manipulated token, the identity token verification resolves the user session based on the provided sid without verifying that the subject sub claim in the token matches the user associated with that session. Consequently, the API returns the victim's session data. An attacker with low privileges can exploit this to read and write a victim's account profile, change the recovery email, and perform a full account takeover via password reset.

A flaw was found in the user update mechanism of the Keycloak Admin REST API. When Fine-Grained Admin Permissions are enabled, the system fails to check for specific password reset authorizations during a general user profile update. This allows a delegated administrator, who should be restricted from resetting passwords, to change a user's credentials and take over their account.

A flaw was found in the token exchange mechanism of Keycloak. When using Standard Token Exchange V2, the system issues new tokens with a fresh lifetime based on the requester clients configuration instead of limiting it to the original tokens expiration. This issue allows an authenticated requester to indefinitely extend access for service accounts by repeatedly exchanging tokens, even if the original client has been disabled by an administrator.

A vulnerability was found in Keycloaks Standard Token Exchange V2 implementation within the org.keycloak.protocol.oidc.tokenexchange package. The root cause is that exchanged tokens are issued with a new access-token lifetime derived from the requester clients configuration, failing to bound the new tokens expiration by the subject tokens original expiration time. For service accounts which lack a session ID, this creates a chain where a requester client can indefinitely refresh access by performing a new exchange before the current token expires. The vulnerability persists even if an administrator disables the origin client, as Keycloak continues to accept exchanges of previously exchanged tokens associated with the requester client. An attacker with a valid service-account token and the requester clients credentials can maintain persistent, unauthorized access to resources beyond the intended security lifecycle.

A flaw was found in Keycloaks Pushed Authorization Request PAR implementation. The single-use enforcement for PAR request URIs, as required by RFC 9126 section 4, is bypassed when using the silent authentication path prompt=none. When an existing SSO session is present, the authorization endpoint short-circuits directly to the successful-flow redirect handler. In this specific code path, the PAR consumption logic is never triggered, meaning the pushed request object is not removed from storage after use. Exploitation requires that the realm has PAR enabled, the attacker has valid client credentials to push an authorization request, and an active SSO session exists for the target user. A successful attacker can replay the requesturi multiple times to mint distinct, fully redeemable authorization codes for the same user without requiring the resource owner to re-authenticate. This allows for unauthorized token generation and violates the single-use guarantee required for FAPI-2 and RFC 9126 compliant deployments.

A flaw was found in the authentication session management of Keycloak, an identity and access management solution. The issue occurs when an administrator enforces a stronger authentication flow, such as mandatory two-factor authentication (2FA) setup, through a client policy. A user can bypass this requirement by manually visiting a specific session restart web link during the login process. This action clears the internal markers that track the required security steps, allowing the user to log in with only a password and gain access without completing the mandated 2FA setup.

A Missing Authorization vulnerability was discovered in Keycloaks Admin REST API. The flaw exists in the way the API resolves client resources using the per-request in-memory cache in the org.keycloak.models.cache.infinispan component. The cache is keyed by client UUID alone and does not perform a realm ownership validation when a resource is retrieved. An authenticated attacker with the create-realm role in the master realm can exploit this by creating a new realm and then addressing a master realm client using its UUID through the attacker-controlled realms API path. If the master realm client is present in the per-request cache, the system returns or updates the master client instead of enforcing realm boundaries. Successful exploitation allows an attacker to: Read client details, including credentials of confidential clients in the master realm.

Overwrite client configurations, such as injecting arbitrary redirect URIs into built-in master clients like admin-cli or security-admin-console.

Turn the master authorization endpoint into an open redirect.

Potentially affect other resource types that utilize the same per-request cache pattern.

A Missing Authorization flaw was found in the Keycloak Admin REST API. The endpoint for deleting user credentials (DELETE /admin/realms/{realm}/users/{id}/credentials/{credentialId}) only verifies generic user management permissions (requireManage) and fails to enforce fine-grained reset-password authorization (requireResetPassword). This issue affects deployments where Fine-Grained Admin Permissions (FGAP) are enabled. An attacker with delegated administrator privileges, who is granted manage permissions but explicitly denied reset-password authority via a negative policy, can bypass this restriction. By invoking the credential deletion endpoint, the attacker can successfully delete stored password credentials for managed users. The concrete impact includes: Deleting a user's primary authentication credentials.

Causing account lockout for the victim user.

Performing a targeted denial of service against managed users.

A flaw was found in the org.keycloak.broker.saml package of Keycloak. The SAML identity broker incorrectly handles signed assertions that contain only a holder-of-key SubjectConfirmation. When a bearer confirmation is absent, the broker skips the necessary subject-confirmation validation instead of enforcing proof of possession for the bound key. Exploitation requires that Keycloak is configured as a SAML broker with a trusted upstream provider that issues holder-of-key assertions. An attacker must obtain a valid signed assertion issued for a victim. No authentication or user interaction is required for the replay attack. Successful exploitation allows an attacker to bypass authentication mechanisms, impersonate any victim for whom they have a valid assertion, gain full access to the victim account and downstream applications, and issue new downstream assertions for the victim identity.

A flaw was found in Keycloak's Device Authorization Grant (RFC 8628) flow. The token redemption path in the DeviceGrantType class verifies the user.isEnabled status but fails to consult the BruteForceProtector to check for temporary lockouts. Because Keycloak's brute-force mechanism does not set the enabled flag to false during a temporary lockout, a locked user successfully passes the check. An attacker who possesses a surviving SSO browser session for a target account (established before the lockout) can complete the device verification and consent flow without being prompted for re-authentication. Consequently, the token endpoint issues a valid access token and refresh token while the account remains in a brute-force-locked state. This vulnerability represents a failure to include the Device Authorization Grant path in the fixes previously implemented for CIBA (CVE-2026-9798 and CVE-2026-16103).

A flaw was found in the first-broker-login flow of the Keycloak identity management service. When a user links a social identity provider account to their local account, the verification proof generated is not strictly bound to the specific upstream identity being verified. This allows an attacker with a different account on the same social provider to intercept the process and link their own account to the victim's local profile, gaining unauthorized access.

A flaw was found in the SAML implementation of Keycloak, an open-source identity and access management solution. The SAML Artifact Resolution and ECP SOAP endpoints do not properly limit the size or complexity of incoming XML requests. An unauthenticated remote attacker can exploit this by sending specially crafted, large XML messages that cause the server to consume excessive memory. This leads to the application running out of memory and crashing, resulting in a denial of service for all users.

A Missing Authorization flaw (CWE-862) was identified in the JWT Bearer authorization grant (urn:ietf:params:oauth:grant-type:jwt-bearer) in Keycloak. The vulnerability exists in the JWTAuthorizationGrantType.process function, which fails to verify the client.isConsentRequired flag or check for a stored UserConsentModel before issuing an access token. While other user-facing grants like Resource Owner Password Credentials (ROPC) explicitly refuse consent-required clients, and interactive grants verify stored consent, the JWT Bearer grant bypasses these checks entirely. To exploit this flaw, an attacker must have access to a confidential client credentials and a valid JWT assertion for a target user signed by an allow-listed Identity Provider (IdP). Successful exploitation allows an attacker to: Obtain a valid access token for a target user without their consent.

Access protected resources and APIs on behalf of the user.

Bypass administrative security policies intended to gate client access behind explicit user approval.

A flaw was found in Keycloak where the theme localization endpoints (/resources/master/common/{locale} and /admin/{realm}/console/messages.json) fail to validate or limit the locale tags provided in the request. Each unique locale tag results in a new entry being created in an unbounded in-memory cache within the theme message system. An unauthenticated remote attacker can exploit this by sending a high volume of HTTP GET requests containing unique BCP 47 locale tags. Because the cache is permanent and has no size limit, this leads to continuous heap memory consumption. Successful exploitation allows an attacker to exhaust the JVM heap memory, leading to an OutOfMemoryError and causing the Keycloak service to terminate, resulting in a complete denial of service.

A flaw was found in the SAML broker component of Keycloak, an identity and access management solution. When configured as a SAML broker using the IdP-Initiated flow, Keycloak fails to enforce the OneTimeUse condition in SAML assertions. This allows an attacker who captures a valid, unused assertion to replay it multiple times. Successful exploitation could allow an attacker to hijack a user's session and gain unauthorized access to the system as that user.

A state-based policy bypass vulnerability was discovered in Keycloak's client policy engine. The flaw exists in the way the access-type condition evaluates UPDATE operations. Specifically, the condition checks the old client state instead of the proposed new state during an update. An attacker with low privileges, such as delegated client management permissions or a valid dynamic registration token, can exploit this by creating a public client and subsequently updating it to a confidential client. Because the policy engine still perceives the client as public during the update process, it fails to trigger the confidential-client policy profile. This allows the attacker to configure a confidential client with weak authentication (e.g., client-secret) even when the realm policy mandates stronger methods like client-jwt. Successful exploitation allows an attacker to persist non-compliant confidential clients, undermining realm-level security hardening.

A vulnerability was found in Keycloak where authenticated users can bypass authorization services time policies. When requesting a User-Managed Access (UMA) permission, a caller can supply a claim token containing forged kc.time.datetime values. Keycloak merges these caller-supplied claims after the server-generated time attributes, allowing the forged values to overwrite the server clock during policy evaluation. This allows an attacker to obtain Resource Permission Tokens (RPTs) outside of the time windows configured by administrators, effectively defeating temporal access controls such as maintenance windows or off-hours access denials.

A vulnerability was found in Keycloak where authenticated users can bypass authorization services time policies. When requesting a User-Managed Access (UMA) permission, a caller can supply a claim token containing forged kc.time.datetime values. Keycloak merges these caller-supplied claims after the server-generated time attributes, allowing the forged values to overwrite the server clock during policy evaluation. This allows an attacker to obtain Resource Permission Tokens (RPTs) outside of the time windows configured by administrators, effectively defeating temporal access controls such as maintenance windows or off-hours access denials.

A Broken Access Control vulnerability was identified in Keycloaks Fine-Grained Admin Permissions V2 (FGAP V2) implementation. The flaw exists in the POST /admin/realms/{realm}/users endpoint, where the server fails to validate group membership permissions within the user creation payload. While Keycloak correctly enforces manage-membership scopes for existing users, it misses this check during the initial user creation process. A sub-administrator with user create scope but restricted group manage-membership scope can successfully assign a new user to unauthorized groups by including them in the creation request. Concrete impact: An attacker with sub-admin privileges can elevate the permissions of new users, grant them access to restricted data by placing them in sensitive groups, and bypass the security boundaries established by FGAP V2.

A Missing Authorization vulnerability was found in the Keycloak full-scope-disabled client-policy executor. When the executor is configured with auto-configure disabled, it fails to properly validate client creation or update requests that omit the fullScopeAllowed field. Because the server defaults to fullScopeAllowed=true for non-consent clients, an attacker with delegated client creation privileges can bypass the intended restriction. Successful exploitation allows an attacker to create a client that possesses full scope access within the realm, even when a policy is active to prevent it. This results in the issuance of tokens containing role mappings that should have been restricted by the realm policy.

A flaw was found in the SAML protocol implementation of Keycloak, an open-source identity and access management solution. The issue occurs when Keycloak handles SAML authentication requests using the HTTP-Redirect binding. If a client is configured with a wildcard redirect URL, an attacker can craft a request that includes malicious parameters. When a user authenticates, Keycloak appends its legitimate response to the attacker's parameters. This can cause some service providers to process the attacker's data instead of the real login information, potentially leading to a user being logged into the wrong account.

A flaw was found in the client policy enforcement mechanism of Keycloak. The issue occurs when the system checks group membership by name instead of a unique identifier. An attacker with client management privileges could bypass security policies by joining a group with a matching name in a different part of the group hierarchy, potentially allowing them to register or update clients without following required security hardening profiles.