Red Hat Build Keycloak
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By the Year
In 2026 there have been 51 vulnerabilities in Red Hat Build Keycloak with an average score of 5.6 out of ten. Last year, in 2025 Build Keycloak had 27 security vulnerabilities published. That is, 24 more vulnerabilities have already been reported in 2026 as compared to last year. Last year, the average CVE base score was greater by 0.04
| Year | Vulnerabilities | Average Score |
|---|---|---|
| 2026 | 51 | 5.59 |
| 2025 | 27 | 5.63 |
| 2024 | 38 | 6.24 |
| 2023 | 3 | 5.63 |
It may take a day or so for new Build Keycloak vulnerabilities to show up in the stats or in the list of recent security vulnerabilities. Additionally vulnerabilities may be tagged under a different product or component name.
Recent Red Hat Build Keycloak Security Vulnerabilities
Keycloak Cross-Session Verification Key Allows Upstream IdP Account Consuming
CVE-2026-9087
6.4 - Medium
- May 20, 2026
A flaw was found in Keycloak. The cross-session verification proof is keyed only by (local userId, idpAlias) and is not bound to the upstream identity that was actually verified, so a second upstream account on the same IdP can consume it and get linked to the victim's local account.
Insecure Direct Object Reference / IDOR
Keycloak OIDC implicit flow bypass & token leakage
CVE-2026-7571
7.1 - High
- May 19, 2026
A flaw was found in Keycloak. A low-privilege user, with knowledge of user credentials and client ID, can bypass a security control intended to disable the implicit flow in OpenID Connect (OIDC) clients. By manipulating client data during a session restart, an attacker can obtain an access token that should not be available. This vulnerability can also lead to the exposure of these access tokens in server logs, proxy logs, and HTTP Referrer headers, resulting in sensitive information disclosure.
Assumed-Immutable Parameter Tampering
Session Fixation in Keycloak /login-actions restart endpoint (SSO takeover)
CVE-2026-7507
7.5 - High
- May 19, 2026
A session fixation vulnerability was found in Keycloak's login-actions endpoints. An unauthenticated attacker could exploit this flaw by pre-creating an authentication session and tricking a victim into visiting a maliciously crafted link. By leveraging the /login-actions/restart endpointwhich processes session handles without adequate CSRF protection or cookie ownership validationan attacker can reset the authentication flow state. This causes Single Sign-On (SSO) to authenticate the victim transparently upon clicking the link, allowing the attacker to hijack the required-action form without needing the victim's credentials. A successful exploit could lead to complete account takeover, including highly privileged administrative accounts.
Authentication Bypass by Spoofing
Keycloak Wildcard Redirect URI Validation Bypass (CVE-2026-7504)
CVE-2026-7504
8.1 - High
- May 19, 2026
A flaw was found in Keycloak's URL validation logic during redirect operations. By crafting a malicious request, an attacker could bypass validation to redirect users to unauthorized URLs, potentially leading to the exposure of sensitive information within the domain or facilitating further attacks. This vulnerability specifically affects Keycloak clients configured with a wildcard (*) in the "Valid Redirect URIs" field and requires user interaction to be successfully exploited. The issue stems from a discrepancy in how Keycloak and the underlying Java URI implementation handle the user-info component of a URL. If a malicious redirect URL is constructed using multiple @ characters in the user-info section, Java's URI parser fails to extract the user-info, leaving only the raw authority field. Consequently, Keycloak's validation check fails to detect the malformed user-info, falls back to a wildcard comparison, and incorrectly permits the malicious redirect.
Open Redirect
Keycloak WebAuthn Replay of ExecuteActionsActionToken
CVE-2026-37982
6.8 - Medium
- May 19, 2026
A flaw was found in Keycloak. This authentication vulnerability allows a remote attacker to replay `ExecuteActionsActionToken` tokens within Keycloak's WebAuthn (Web Authentication) flow. By intercepting an execute-actions email link, an attacker can register their own authenticator to a victim's account. This leads to unauthorized enrollment of a hardware-backed credential, enabling persistent account takeover.
Authentication Bypass by Capture-replay
Keycloak OIDC Introspection Audience Bypass Vulnerability
CVE-2026-37979
6.5 - Medium
- May 19, 2026
A flaw was found in Keycloak. This access control vulnerability in Keycloak's OpenID Connect (OIDC) token introspection endpoint allows a confidential client to bypass audience restrictions. An attacker-controlled client with valid credentials can retrieve sensitive token claims intended for other resource servers, compromising the confidentiality of lightweight access tokens. This issue can be exploited remotely by any confidential client in the realm with valid credentials.
Authorization
Keycloak Admin API PII Leak via view-clients evaluate-scopes
CVE-2026-37978
4.9 - Medium
- May 19, 2026
A flaw was found in Keycloak. A low-privilege administrator with the 'view-clients' role can exploit this by invoking the 'evaluate-scopes' Admin API endpoints with an arbitrary user ID (userId) parameter. This vulnerability allows for cross-role personally identifiable information (PII) leakage, enabling unauthorized visibility into user identities and authorizations across the realm. Exploitation is possible remotely via network access to the Admin API.
Insecure Direct Object Reference / IDOR
Keycloak SAML XML DoS: Unauth Remote Attacker via Crafted Input
CVE-2026-7307
7.5 - High
- May 19, 2026
A flaw was found in Keycloak. A remote, unauthenticated attacker can send a specially crafted XML input to the Security Assertion Markup Language (SAML) endpoint. This malicious input can cause high CPU usage and worker thread starvation, leading to a Denial of Service (DoS) where the server becomes unavailable.
Improper Validation of Syntactic Correctness of Input
Keycloak: Broken Access Control in Account Resources Lookup Endpoint
CVE-2026-37981
4.3 - Medium
- May 19, 2026
A flaw was found in Keycloak. A broken access control vulnerability in the Account Resources user lookup endpoint allows a remote authenticated user, who owns at least one User-Managed Access (UMA) resource, to enumerate and harvest personally identifiable information (PII) for all realm users. By sending crafted requests with arbitrary usernames or email values, the endpoint returns full profile objects for unrelated users. This leads to broad profile-level information disclosure.
Insufficient Granularity of Access Control
Keycloak IDOR in Authorization Services API
CVE-2026-4630
6.8 - Medium
- May 19, 2026
A flaw was found in Keycloak. An authenticated client could exploit an Insecure Direct Object Reference (IDOR) vulnerability in the Authorization Services Protection API endpoint. By knowing or obtaining a resource's unique identifier (UUID) belonging to another Resource Server within the same realm, the client could bypass authorization checks. This allows the client to perform unauthorized GET, PUT, and DELETE operations on resources, leading to information disclosure and potential unauthorized modification or deletion of data.
Insecure Direct Object Reference / IDOR
Keycloak OIDC Introspection ignores realm-level notBefore revocation
CVE-2026-8922
5.4 - Medium
- May 19, 2026
A flaw was found in Keycloak. When both realm-level and client-level `notBefore` revocation policies are configured, Keycloak's OpenID Connect (OIDC) Introspection feature fails to properly honor the realm-level policy. This allows tokens that should have been revoked to remain active, potentially leading to unauthorized access or continued session validity. This could impact the security of systems utilizing Keycloak for identity and access management.
Incorrect Implementation of Authentication Algorithm
Keycloak WebAuthn Policy Bypass via Client JS Manipulation
CVE-2026-8830
4.3 - Medium
- May 19, 2026
A flaw was found in Keycloak. An authenticated user can bypass configured WebAuthn policies during credential registration by manipulating client-side JavaScript. This occurs because the server-side processAction() fails to validate that the newly created credential's parameters, such as public key algorithms, match the realm's configured WebAuthn policies. This could lead to the creation of credentials that do not adhere to administrative security requirements, potentially weakening the overall security posture of the system by allowing non-compliant authentication methods.
Use of Client-Side Authentication
Privilege Escalation: Keycloak Account REST API Partially Disabled
CVE-2026-7500
5.4 - Medium
- April 30, 2026
When Keycloak is started with `--features-disabled=account,account-api`, the Account REST API is only partially disabled. Five endpoints under the versioned path `/account/v1alpha1` remain fully functional including both read and write operations because they lack the `checkAccountApiEnabled()` gate that correctly blocks four other endpoints in the same REST service class. The user needs to have permissions to use the API.
forced browsing
Keycloak: Stored XSS via org.alias in Login Page (manage-realm/organizations)
CVE-2026-37980
6.9 - Medium
- April 14, 2026
A flaw was found in Keycloak, specifically in the organization selection login page. A remote attacker with `manage-realm` or `manage-organizations` administrative privileges can exploit a Stored Cross-Site Scripting (XSS) vulnerability. This flaw occurs because the `organization.alias` is placed into an inline JavaScript `onclick` handler, allowing a crafted JavaScript payload to execute in a user's browser when they view the login page. Successful exploitation enables arbitrary JavaScript execution, potentially leading to session theft, unauthorized account actions, or further attacks against users of the affected realm.
XSS
Keycloak CORS Header Injection in UMA Token Endpoint via Unsigned azp Claim
CVE-2026-37977
3.7 - Low
- April 06, 2026
A flaw was found in Keycloak. A remote attacker can exploit a Cross-Origin Resource Sharing (CORS) header injection vulnerability in Keycloak's User-Managed Access (UMA) token endpoint. This flaw occurs because the `azp` claim from a client-supplied JSON Web Token (JWT) is used to set the `Access-Control-Allow-Origin` header before the JWT signature is validated. When a specially crafted JWT with an attacker-controlled `azp` value is processed, this value is reflected as the CORS origin, even if the grant is later rejected. This can lead to the exposure of low-sensitivity information from authorization server error responses, weakening origin isolation, but only when a target client is misconfigured with `webOrigins: ["*"]`.
Origin Validation Error
Keycloak una_protection role: UMA policy bypass to access others' resources
CVE-2026-4636
8.1 - High
- April 02, 2026
A flaw was found in Keycloak. An authenticated user with the uma_protection role can bypass User-Managed Access (UMA) policy validation. This allows the attacker to include resource identifiers owned by other users in a policy creation request, even if the URL path specifies an attacker-owned resource. Consequently, the attacker gains unauthorized permissions to victim-owned resources, enabling them to obtain a Requesting Party Token (RPT) and access sensitive information or perform unauthorized actions.
Incorrect Behavior Order: Authorization Before Parsing and Canonicalization
Keycloak OIDC Token Endpoint DoS via Excessively Long Scope Parameter
CVE-2026-4634
7.5 - High
- April 02, 2026
A flaw was found in Keycloak. An unauthenticated attacker can exploit this vulnerability by sending a specially crafted POST request with an excessively long scope parameter to the OpenID Connect (OIDC) token endpoint. This leads to high resource consumption and prolonged processing times, ultimately resulting in a Denial of Service (DoS) for the Keycloak server.
Excessive Platform Resource Consumption within a Loop
Keycloak SingleUseObjectProvider Lacks Isolation, Enabling Token Replay
CVE-2026-4325
5.3 - Medium
- April 02, 2026
A flaw was found in Keycloak. The SingleUseObjectProvider, a global key-value store, lacks proper type and namespace isolation. This vulnerability allows an attacker to delete arbitrary single-use entries, which can enable the replay of consumed action tokens, such as password reset links. This could lead to unauthorized access or account compromise.
Separation of Privilege
Keycloak: SingleUseObjectProvider Lacks Isolation, Enabling Unauth Code Forgery
CVE-2026-4282
7.4 - High
- April 02, 2026
A flaw was found in Keycloak. The SingleUseObjectProvider, a global key-value store, lacks proper type and namespace isolation. This vulnerability allows an unauthenticated attacker to forge authorization codes. Successful exploitation can lead to the creation of admin-capable access tokens, resulting in privilege escalation.
Separation of Privilege
Keycloak Redirect URI Wildcard Bypass Leads to Token Theft
CVE-2026-3872
7.3 - High
- April 02, 2026
A flaw was found in Keycloak. This issue allows an attacker, who controls another path on the same web server, to bypass the allowed path in redirect Uniform Resource Identifiers (URIs) that use a wildcard. A successful attack may lead to the theft of an access token, resulting in information disclosure.
Open Redirect
Keycloak Priv Escalation via Misconfigured manage-clients as manage-permissions
CVE-2026-3121
6.5 - Medium
- March 26, 2026
A flaw was found in Keycloak. An administrator with `manage-clients` permission can exploit a misconfiguration where this permission is equivalent to `manage-permissions`. This allows the administrator to escalate privileges and gain control over roles, users, or other administrative functions within the realm. This privilege escalation can occur when admin permissions are enabled at the realm level.
Incorrect Privilege Assignment
Keycloak UMA Permission Ticket Enum - CVE-2026-3190
CVE-2026-3190
4.3 - Medium
- March 26, 2026
A flaw was found in Keycloak. The User-Managed Access (UMA) 2.0 Protection API endpoint for permission tickets fails to enforce the `uma_protection` role check. This allows any authenticated user with a token issued for a resource server client, even without the `uma_protection` role, to enumerate all permission tickets in the system. This vulnerability partial leads to information disclosure.
Improper Handling of Insufficient Permissions or Privileges
Keycloak SSRF via client_session_host in Refresh Token
CVE-2026-4874
3.1 - Low
- March 26, 2026
A flaw was found in Keycloak. An authenticated attacker can perform Server-Side Request Forgery (SSRF) by manipulating the `client_session_host` parameter during refresh token requests. This occurs when a Keycloak client is configured to use the `backchannel.logout.url` with the `application.session.host` placeholder. Successful exploitation allows the attacker to make HTTP requests from the Keycloak servers network context, potentially probing internal networks or internal APIs, leading to information disclosure.
SSRF
Keycloak ID First Login Error Message CVE-2026-4633: User Enumeration
CVE-2026-4633
3.7 - Low
- March 23, 2026
A flaw was found in Keycloak. A remote attacker can exploit differential error messages during the identity-first login flow when Organizations are enabled. This vulnerability allows an attacker to determine the existence of users, leading to information disclosure through user enumeration.
Generation of Error Message Containing Sensitive Information
Keycloak UMA resource_set Endpoint: Access Control Bypass via PUT
CVE-2026-4628
4.3 - Medium
- March 23, 2026
A flaw was found in Keycloak. An improper Access Control vulnerability in Keycloaks User-Managed Access (UMA) resource_set endpoint allows attackers with valid credentials to bypass the allowRemoteResourceManagement=false restriction. This occurs due to incomplete enforcement of access control checks on PUT operations to the resource_set endpoint. This issue enables unauthorized modification of protected resources, impacting data integrity.
Authorization
Keycloak Improper HTTP Redirect Handling leads to Info Disclosure
CVE-2026-4366
5.8 - Medium
- March 18, 2026
A flaw was identified in Keycloak, an identity and access management solution, where it improperly follows HTTP redirects when processing certain client configuration requests. This behavior allows an attacker to trick the server into making unintended requests to internal or restricted resources. As a result, sensitive internal services such as cloud metadata endpoints could be accessed. This issue may lead to information disclosure and enable attackers to map internal network infrastructure.
SSRF
Keycloak DoS via max SAMLRequest over SAML Redirect Binding
CVE-2026-2575
5.3 - Medium
- March 18, 2026
A flaw was found in Keycloak. An unauthenticated remote attacker can trigger an application level Denial of Service (DoS) by sending a highly compressed SAMLRequest through the SAML Redirect Binding. The server fails to enforce size limits during DEFLATE decompression, leading to an OutOfMemoryError (OOM) and subsequent process termination. This vulnerability allows an attacker to disrupt the availability of the service.
Data Amplification
Keycloak SAML Endpoint Bypass via Crafted IdP Response
CVE-2026-2603
8.1 - High
- March 18, 2026
A flaw was found in Keycloak. A remote attacker could bypass security controls by sending a valid SAML response from an external Identity Provider (IdP) to the Keycloak SAML endpoint for IdP-initiated broker logins. This allows the attacker to complete broker logins even when the SAML Identity Provider is disabled, leading to unauthorized authentication.
Missing Authentication for Critical Function
Keycloak SAML Broker Unvalidated Encrypted Assertion Attack
CVE-2026-2092
7.7 - High
- March 18, 2026
A flaw was found in Keycloak. Keycloak's Security Assertion Markup Language (SAML) broker endpoint does not properly validate encrypted assertions when the overall SAML response is not signed. An attacker with a valid signed SAML assertion can exploit this by crafting a malicious SAML response. This allows the attacker to inject an encrypted assertion for an arbitrary principal, leading to unauthorized access and potential information disclosure.
Improper Validation of Specified Type of Input
Keycloak Admin API Auth Bypass: Org Membership Enumeration
CVE-2026-2366
3.1 - Low
- March 12, 2026
A flaw was found in Keycloak. An authorization bypass vulnerability in the Keycloak Admin API allows any authenticated user, even those without administrative privileges, to enumerate the organization memberships of other users. This information disclosure occurs if the attacker knows the victim's unique identifier (UUID) and the Organizations feature is enabled.
Insecure Direct Object Reference / IDOR
Keycloak REST API Privilege Escalation via MFA Credential Delete
CVE-2026-3429
4.2 - Medium
- March 11, 2026
A flaw was identified in the Account REST API of Keycloak that allows a user authenticated at a lower security level to perform sensitive actions intended only for higher-assurance sessions. Specifically, an attacker who has already obtained a victims password can delete the victims registered MFA/OTP credential without first proving possession of that factor. The attacker can then register their own MFA device, effectively taking full control of the account. This weakness undermines the intended protection provided by multi-factor authentication.
Authorization
Keycloak UserResource viewusers Role IDP Disclosure
CVE-2026-3911
2.7 - Low
- March 11, 2026
A flaw was found in Keycloak. An authenticated user with the view-users role could exploit a vulnerability in the UserResource component. By accessing a specific administrative endpoint, this user could improperly retrieve user attributes that were configured to be hidden. This unauthorized information disclosure could expose sensitive user data.
Privacy violation
Keycloak SAML Broker Auth Bypass via Disabled Client
CVE-2026-3047
8.8 - High
- March 05, 2026
A flaw was found in org.keycloak.broker.saml. When a disabled Security Assertion Markup Language (SAML) client is configured as an Identity Provider (IdP)-initiated broker landing target, it can still complete the login process and establish a Single Sign-On (SSO) session. This allows a remote attacker to gain unauthorized access to other enabled clients without re-authentication, effectively bypassing security restrictions.
Authentication Bypass by Primary Weakness
Keycloak IdentityBroker Auth Bypass via Disabled IdP
CVE-2026-3009
8.1 - High
- March 05, 2026
A security flaw in the IdentityBrokerService.performLogin endpoint of Keycloak allows authentication to proceed using an Identity Provider (IdP) even after it has been disabled by an administrator. An attacker who knows the IdP alias can reuse a previously generated login request to bypass the administrative restriction. This undermines access control enforcement and may allow unauthorized authentication through a disabled external provider.
AuthZ
Keycloak WebAuthn Auth Attestation Bypass (fmt none)
CVE-2025-12150
3.1 - Low
- February 27, 2026
A flaw was found in Keycloaks WebAuthn registration component. This vulnerability allows an attacker to bypass the configured attestation policy and register untrusted or forged authenticators via submission of an attestation object with fmt: "none", even when the realm is configured to require direct attestation. This can lead to weakened authentication integrity and unauthorized authenticator registration.
Improper Verification of Cryptographic Signature
Keycloak RBAC Bypass: Unauthorized Attribute Modification via manageusers
CVE-2026-0871
4.9 - Medium
- February 27, 2026
A flaw was found in Keycloak. An administrator with `manage-users` permission can bypass the "Only administrators can view" setting for unmanaged attributes, allowing them to modify these attributes. This improper access control can lead to unauthorized changes to user profiles, even when the system is configured to restrict such modifications.
Incorrect Privilege Assignment
Keycloak Docker v2 Auth: Tokens Issued Post-Disable (CVE-2026-2733)
CVE-2026-2733
3.8 - Low
- February 19, 2026
A flaw was identified in the Docker v2 authentication endpoint of Keycloak, where tokens continue to be issued even after a Docker registry client has been administratively disabled. This means that turning the client Enabled setting to OFF does not fully prevent access. As a result, previously valid credentials can still be used to obtain authentication tokens. This weakens administrative controls and could allow unintended access to container registry resources.
AuthZ
Verbose Logging Exposes Auth & Cookie Headers in Keycloak
CVE-2025-11537
5 - Medium
- February 10, 2026
A flaw was found in Keycloak. When the logging format is configured to a verbose, user-supplied pattern (such as the pre-defined 'long' pattern), sensitive headers including Authorization and Cookie are disclosed to the logs in cleartext. An attacker with read access to the log files can extract these credentials (e.g., bearer tokens, session cookies) and use them to impersonate users, leading to a full account compromise.
Improper Output Neutralization for Logs
Keycloak UMA Policy Bypass via Owner Check Leak
CVE-2025-14778
5.4 - Medium
- February 09, 2026
A flaw was found in Keycloak. A significant Broken Access Control vulnerability exists in the UserManagedPermissionService (UMA Protection API). When updating or deleting a UMA policy associated with multiple resources, the authorization check only verifies the caller's ownership against the first resource in the policy's list. This allows a user (Owner A) who owns one resource (RA) to update a shared policy and modify authorization rules for other resources (e.g., RB) in that same policy, even if those other resources are owned by a different user (Owner B). This constitutes a horizontal privilege escalation.
Incorrect Privilege Assignment
Keycloak JWT Signature Bypass Allows Unauthorized Org Self-Registration
CVE-2026-1529
8.1 - High
- February 09, 2026
A flaw was found in Keycloak. An attacker can exploit this vulnerability by modifying the organization ID and target email within a legitimate invitation token's JSON Web Token (JWT) payload. This lack of cryptographic signature verification allows the attacker to successfully self-register into an unauthorized organization, leading to unauthorized access.
Improper Verification of Cryptographic Signature
Keycloak JWT Authorization Grant Token Issued Even for Disabled IdP
CVE-2026-1486
8.8 - High
- February 09, 2026
A flaw was found in Keycloak. A vulnerability exists in the jwt-authorization-grant flow where the server fails to verify if an Identity Provider (IdP) is enabled before issuing tokens. The issuer lookup mechanism (lookupIdentityProviderFromIssuer) retrieves the IdP configuration but does not filter for isEnabled=false. If an administrator disables an IdP (e.g., due to a compromise or offboarding), an entity possessing that IdP's signing key can still generate valid JWT assertions that Keycloak accepts, resulting in the issuance of valid access tokens.
Improperly Implemented Security Check for Standard
Insufficient backchannel validation in Keycloak CIBA blind SSRF
CVE-2026-1518
2.7 - Low
- February 02, 2026
A flaw was found in Keycloaks CIBA feature where insufficient validation of client-configured backchannel notification endpoints could allow blind server-side requests to internal services.
SSRF
Keycloak /unmanagedAttributes Bypass Lets Admin View Sensitive Custom Attributes
CVE-2025-13881
2.7 - Low
- February 02, 2026
A flaw was found in Keycloak Admin API. This vulnerability allows an administrator with limited privileges to retrieve sensitive custom attributes via the /unmanagedAttributes endpoint, bypassing User Profile visibility settings.
Incorrect Privilege Assignment
Undertow OOM via large servlet param names
CVE-2024-4027
7.5 - High
- January 30, 2026
A flaw was found in Undertow. Servlets using a method that calls HttpServletRequestImpl.getParameterNames() can cause an OutOfMemoryError when the client sends a request with large parameter names. This issue can be exploited by an unauthorized user to cause a remote denial-of-service (DoS) attack.
Improper Input Validation
Keycloak SAML NotOnOrAfter Validation Bypass Enables Session Extension
CVE-2026-1190
3.1 - Low
- January 26, 2026
A flaw was found in Keycloak's SAML brokering functionality. When Keycloak is configured as a client in a Security Assertion Markup Language (SAML) setup, it fails to validate the `NotOnOrAfter` timestamp within the `SubjectConfirmationData`. This allows an attacker to delay the expiration of SAML responses, potentially extending the time a response is considered valid and leading to unexpected session durations or resource consumption.
Missing XML Validation
RedHat Keycloak Admin REST API: Exposed Backend Schema via Improper Access Control
CVE-2025-14083
2.7 - Low
- January 21, 2026
A flaw was found in the Keycloak Admin REST API. This vulnerability allows the exposure of backend schema and rules, potentially leading to targeted attacks or privilege escalation via improper access control.
Authorization
Keycloak Token Exchange BLP Allows Tokens to Disabled Users
CVE-2025-14559
6.5 - Medium
- January 21, 2026
A flaw was found in the keycloak-services component of Keycloak. This vulnerability allows the issuance of access and refresh tokens for disabled users, leading to unauthorized use of previously revoked privileges, via a business logic vulnerability in the Token Exchange implementation when a privileged client invokes the token exchange flow.
Business Logic Errors
Keycloak Refresh Token Rotation Bypass via Atomicity Flaw
CVE-2026-1035
3.1 - Low
- January 21, 2026
A flaw was found in the Keycloak server during refresh token processing, specifically in the TokenManager class responsible for enforcing refresh token reuse policies. When strict refresh token rotation is enabled, the validation and update of refresh token usage are not performed atomically. This allows concurrent refresh requests to bypass single-use enforcement and issue multiple access tokens from the same refresh token. As a result, Keycloaks refresh token rotation hardening can be undermined.
TOCTTOU
Keycloak OIDC DCR leaks internal via arbitrary jwks_uri
CVE-2026-1180
5.8 - Medium
- January 20, 2026
A flaw was identified in Keycloaks OpenID Connect Dynamic Client Registration feature when clients authenticate using private_key_jwt. The issue allows a client to specify an arbitrary jwks_uri, which Keycloak then retrieves without validating the destination. This enables attackers to coerce the Keycloak server into making HTTP requests to internal or restricted network resources. As a result, attackers can probe internal services and cloud metadata endpoints, creating an information disclosure and reconnaissance risk.
SSRF
Keycloak URL Matrix Param Input Validation (CVE-2026-0976)
CVE-2026-0976
3.7 - Low
- January 15, 2026
A flaw was found in Keycloak. This improper input validation vulnerability occurs because Keycloak accepts RFC-compliant matrix parameters in URL path segments, while common reverse proxy configurations may ignore or mishandle them. A remote attacker can craft requests to mask path segments, potentially bypassing proxy-level path filtering. This could expose administrative or sensitive endpoints that operators believe are not externally reachable.
Improper Input Validation
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