Threats Tagged 'cve-2026-11800'

CVE-2026-11800 is a high-severity vulnerability in Red Hat build of Keycloak 26.6 involving improper verification of cryptographic signatures in the JWT Authorization Grant flow. An attacker with valid client credentials can bypass signature verification by exploiting JWT algorithm confusion, allowing creation of unauthorized access tokens. This enables impersonation of any federated user linked to the affected Identity Provider, potentially leading to unauthorized access and privilege escalation. Red Hat has released updated packages in version 26.6.4 addressing this and multiple other security issues. Users are advised to update to the fixed version to mitigate the risk.

Red Hat build of Keycloak 26.6.4 is a standalone server, based on the Keycloak project, that provides authentication and standards-based single sign-on capabilities for web and mobile applications. Security fixes: * Information disclosure via CORS header injection due to unvalidated JWT azp claim (CVE-2026-37977) * Server-Side Request Forgery via OIDC token endpoint manipulation (CVE-2026-4874) * eclipse-vertx/vert.x: Denial of Service via TLS handshake with wildcard server name (CVE-2026-6860) * Improper Access Control on Keycloak Server when the account Account API feature is disabled (CVE-2026-7500) * Policy bypass during WebAuthn credential registration via client-side JavaScript manipulation (CVE-2026-8830) * Security flaw in org.keycloak/keycloak-services (CVE-2026-8922) * Information disclosure through arbitrary filesystem path probing (CVE-2026-9083) * Cross-site scripting (XSS) via case-insensitive URI validation bypass (CVE-2026-9086) * Cross-Session Email Verification Proof Not Bound to Upstream Identity in First-Broker-Login (CVE-2026-9087) * Information disclosure due to user profile permission bypass (CVE-2026-9088) * Group-Admin Escalation to Realm-Admin (CVE-2026-9099) * Privilege escalation due to oversized subject_token JWT (CVE-2026-9704) * Attacker can re-enable and take over disabled clients via Registration Access Token (CVE-2026-9705) * Organization Data Leak After Feature Disabled in Keycloak (CVE-2026-9791) * Security restriction bypass allows unauthorized ROPC token acquisition (CVE-2026-9792) * Information disclosure via SAML ECP endpoint (CVE-2026-9794) * Privilege escalation via improper scope mapping enforcement (CVE-2026-9795) * Unauthorized access to resources via UMA permission ticket bypass (CVE-2026-9799) * Authorization bypass via incorrect URI comparison (CVE-2026-9800) * Denial of Service via malformed LDAP password policy response (CVE-2026-9801) * Unauthorized account access via replayed refresh tokens after cluster restart (CVE-2026-9802) * Denial of Service via malformed Authorization header (CVE-2026-9803)