Medium severity6.8NVD Advisory· Published May 27, 2026· Updated Jun 10, 2026
CVE-2026-9704
CVE-2026-9704
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.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected products
3(expand)+ 1 more
- (no CPE)
- cpe:2.3:a:redhat:build_of_keycloak:-:*:*:*:-:*:*:*
Patches
Vulnerability mechanics
References
4- access.redhat.com/security/cve/CVE-2026-9704nvdMitigationVendor Advisory
- bugzilla.redhat.com/show_bug.cginvdIssue TrackingVendor Advisory
- access.redhat.com/errata/RHSA-2026:25097nvd
- access.redhat.com/errata/RHSA-2026:25098nvd
News mentions
1- Keycloak: Twelve Vulnerabilities Disclosed, One High SeverityVypr Intelligence · May 28, 2026