CVE-2026-4634
CWE-1050Published: April 2, 2026· Updated: Apr 3, 2026
Official Description
A flaw was found in Keycloak. An unauthenticated attacker can exploit this vulnerability by sending a specially crafted POST request with an excessively long scope parameter to the OpenID Connect (OIDC) token endpoint. This leads to high resource consumption and prolonged processing times, ultimately resulting in a Denial of Service (DoS) for the Keycloak server.
Technical Analysis
CVE-2026-4634 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.
The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.
A successful exploit results in availability disruption (denial of service), with a CVSS base score of 7.5.
CVSS v3.1 Vector Breakdown
Exploit & PoC Resources
All References (6)
Quick Facts
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2026-4634 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts