Redhat: >> Build Of Keycloak >> 26.4 Security Vulnerabilities
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.
CVSS Score
7.1
EPSS Score
0.003
Published
2026-05-19
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.
CVSS Score
6.5
EPSS Score
0.004
Published
2026-05-19
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.
CVSS Score
4.3
EPSS Score
0.004
Published
2026-05-19
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.
CVSS Score
6.8
EPSS Score
0.004
Published
2026-05-19
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.
CVSS Score
4.9
EPSS Score
0.004
Published
2026-05-19
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.
CVSS Score
7.5
EPSS Score
0.005
Published
2026-04-02
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.
CVSS Score
8.1
EPSS Score
0.003
Published
2026-04-02
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.
CVSS Score
7.3
EPSS Score
0.004
Published
2026-04-02
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.
CVSS Score
7.4
EPSS Score
0.004
Published
2026-04-02
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.
CVSS Score
5.3
EPSS Score
0.003
Published
2026-04-02