CVE-2026-30949

### Impact The Keycloak authentication adapter does not validate the `azp` (authorized party) claim of Keycloak access tokens against the configured `client-id`. A valid access token issued by the same Keycloak realm for a *different* client application can be used to authenticate as any user on the Parse Server that uses the Keycloak adapter. This enables cross-application account takeover in multi-client Keycloak realms. All Parse Server deployments that use the Keycloak authentication adapter with a Keycloak realm that has multiple client applications are affected. ### Patches The fix replaces the userinfo HTTP call with local JWT verification and enforces `azp` claim validation against the configured `client-id`. ### Workarounds None. ### References - GitHub security advisory: https://github.com/parse-community/parse-server/security/advisories/GHSA-48mh-j4p5-7j9v - Fix Parse Server 9: https://github.com/parse-community/parse-server/releases/tag/9.5.2-alpha.5 - Fix Parse Server 8: https://github.com/parse-community/parse-server/releases/tag/8.6.18

Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to 9.5.2 and 8.6.18, the Keycloak authentication adapter does not validate the azp (authorized party) claim of Keycloak access tokens against the configured client-id. A valid access token issued by the same Keycloak realm for a different client application can be used to authenticate as any user on the Parse Server that uses the Keycloak adapter. This enables cross-application account takeover in multi-client Keycloak realms. All Parse Server deployments that use the Keycloak authentication adapter with a Keycloak realm that has multiple client applications are affected. This vulnerability is fixed in 9.5.2 and 8.6.18.