Improper Validation of Specified Quantity in Input

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 Improper Validation of Specified Quantity in Input in the TokenEndpoint endpoint when an oversized subjecttok...

CVE-2026-9704: Improper Validation of Specified Quantity in Input

A flaw was found in Keycloak. An authenticated user with low privileges can exploit this vulnerability by sending an oversized subjecttoken JSON Web Token JWT to the TokenEndpoint. When the token exceeds a 4000-character limit, it is silently dropped, causing the system to fall back to client...