VULNERABILITY INTELLIGENCE

CVE-2026-9704

CVSS score6.8 MEDIUM
EPSS probability0.32%
CISA KEVNot currently listed
Published2026-05-27
Last modified2026-06-26
CVSS vectorCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N

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.

Weakness classification

  • secalert@redhat.com: CWE-1284

Primary references