CVE-2026-9704 | BDVDB-2026-335348 Detail

Description#

A flaw was found in Keycloak. An authenticated user with low privileges can exploit this vulnerability by sending an oversized subject_token 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 credentials. This allows the user to gain the permissions of the client's service account, leading to privilege escalation.

Impact#

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Exploit#

History#

1. Version 12026-05-27Record published in the CVE List.
2. Version 22026-06-26Most recent update recorded in the CVE List.