CVE-2026-4634

high Red Hat
CVSS v3 Base Score
7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack Characteristics
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Confidentiality
None
Integrity
None
Availability
High
Published: April 2, 2026 (42 days ago)
Last Modified: April 2, 2026
Vendor: Red Hat
Fix Available: ✓ Yes
Source: REDHAT

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.

CWE

CWE-1050

Affected Products

Red Hat build of Keycloak 26.2Red Hat build of Keycloak 26.2.15Red Hat build of Keycloak 26.4Red Hat build of Keycloak 26.4.11

Fix Status

✅ Fix Available

References

🔗 bugzilla.redhat.com 🔗 www.cve.org 🔗 nvd.nist.gov