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: ["*"]`.
Update org.keycloak:keycloak-services to 26.4.13; org.keycloak:keycloak-services to 26.6.3 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scanKeycloak vulnerable to information disclosure via CORS header injection due to unvalidated JWT azp claim affects org.keycloak:keycloak-services (maven), org.keycloak:keycloak-services (maven). Severity is low. 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: ["*"]`.
AI coding agents often install or upgrade packages automatically in maven. A low vulnerability in a dependency can be pulled into a project through a normal install or update without a human reviewing the change, expanding the blast radius from a single package to every agent workspace that depends on it.
| Package | Affected range |
|---|
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: ["*"]`.
Update org.keycloak:keycloak-services to 26.4.13; org.keycloak:keycloak-services to 26.6.3 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scanKeycloak vulnerable to information disclosure via CORS header injection due to unvalidated JWT azp claim affects org.keycloak:keycloak-services (maven), org.keycloak:keycloak-services (maven). Severity is low. 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: ["*"]`.
AI coding agents often install or upgrade packages automatically in maven. A low vulnerability in a dependency can be pulled into a project through a normal install or update without a human reviewing the change, expanding the blast radius from a single package to every agent workspace that depends on it.
| Package | Affected range |
|---|
| Fixed version |
|---|
| org.keycloak:keycloak-servicesmaven | <26.4.13 | 26.4.13 |
|---|---|---|
| org.keycloak:keycloak-servicesmaven | >=26.5.0,<26.6.3 | 26.6.3 |
Fixed versions are reported by the source feed; confirm compatibility before updating.
Reported by GitHub Security Advisories (ghsa).
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL Guard| Fixed version |
|---|
| org.keycloak:keycloak-servicesmaven | <26.4.13 | 26.4.13 |
|---|---|---|
| org.keycloak:keycloak-servicesmaven | >=26.5.0,<26.6.3 | 26.6.3 |
Fixed versions are reported by the source feed; confirm compatibility before updating.
Reported by GitHub Security Advisories (ghsa).
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL Guard