Keycloak vulnerable to information disclosure via CORS header injection due to unvalidated JWT azp claim

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...

GHSA-5V8V-XVJV-57X7 Keycloak vulnerable to information disclosure via CORS header injection due to unvalidated JWT azp claim

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...

EUVD-2026-19201

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...

CVE-2026-37977

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...

CVE-2026-37977 Keycloak: org.keycloak.protocol.oidc.grants.ciba: keycloak: information disclosure via cors header injection due to unvalidated jwt azp claim

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...

CVE-2026-37977

CVE-2026-37977 affects Keycloak’s User-Managed Access (UMA) token endpoint. A flaw in CORS handling arises when the azp claim from a client-supplied JWT is used to set the Access-Control-Allow-Origin header before JWT validation, allowing an attacker-controlled origin to be reflected in responses...

CVE-2026-37977

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...

Origin Validation Error

Overview org.keycloak:keycloak-services is an open source identity and access management solution for modern applications and services. Affected versions of this package are vulnerable to Origin Validation Error in the UMA token endpoint when the azp claim from a client-supplied JWT is used to se...