Flaw in Keycloak Services Affects JWT Authorization Grant Flow
CVE-2026-117627

5.4MEDIUM

Key Information:

Vendor

Red Hat
Status
Red Hat Build Of Keycloak
Red Hat Single Sign-on 7
Vendor
CVE Published:
29 October 2026

What is CVE-2026-117627?

A vulnerability exists in the keycloak-services component's JWT Authorization Grant implementation. Specifically, when configured with OIDC or Google identity providers under certain login restrictions—such as claim filtering—the expected checks are bypassed during the JWT-based grant flow. This oversight permits authenticated clients to acquire access tokens intended for other users, effectively circumventing restrictions that should have enforced proper user authentication. This flaw emphasizes the need for rigorous checks in authorization flows to prevent unauthorized access.

References

https://access.redhat.com/security/cve/CVE-2026-117627
vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2561959
issue-trackingx_refsource_REDHAT

CVSS V3.1

Score:
5.4
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
Low
Availability:
Low
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Red Hat would like to thank Hassan Akaou for reporting this issue.
.