CVE-2026-9704
HIGH EPSS 23.7%
Published May 27, 20261mo ago · Modified Jun 17, 20261w ago
8.8 CVSS 3.1
Published May 27, 2026 1mo ago
Last Modified Jun 17, 2026 1w ago
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.
CVSS Details
Base Score
Exploitability
Impact
Vector string
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Attack Vector Network
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality High
Integrity High
Availability High
Threat Intelligence
EPSS Exploit Probability
23.7% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available
Weaknesses 1
CWE-1284
Affected Products 1
| Vendor | Product | Version | Range |
|---|---|---|---|
| redhat | build_of_keycloak | * | any |
References 4
- access.redhat.com https://access.redhat.com/errata/RHSA-2026:25097
- access.redhat.com https://access.redhat.com/errata/RHSA-2026:25098
- access.redhat.com https://access.redhat.com/security/cve/CVE-2026-9704
- bugzilla.redhat.com https://bugzilla.redhat.com/show_bug.cgi?id=2481877
Remediation
No remediation data recorded yet
Check vendor advisories and the NVD entry for patch availability.