CVE-2026-4634

  1. OpenCVE
  2. Vulnerabilities (CVE)
  3. CVE-2026-4634
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.

7.5 /10

CVSS v3 : HIGH

V3 Legend

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References
Link Resource
https://access.redhat.com/errata/RHSA-2026:6475 Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:6476 Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:6477 Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:6478 Vendor Advisory
https://access.redhat.com/security/cve/CVE-2026-4634 Vendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2450250 Issue Tracking Vendor Advisory
Configurations

Configuration 1 (hide)

OR cpe:2.3:a:redhat:build_of_keycloak:-:*:*:*:text-only:*:*:*
cpe:2.3:a:redhat:build_of_keycloak:26.2:*:*:*:text-only:*:*:*
cpe:2.3:a:redhat:build_of_keycloak:26.2.15:*:*:*:text-only:*:*:*
cpe:2.3:a:redhat:build_of_keycloak:26.4:*:*:*:text-only:*:*:*
cpe:2.3:a:redhat:build_of_keycloak:26.4.11:*:*:*:text-only:*:*:*
History

16 Apr 2026, 20:50

Type Values Removed Values Added
First Time Redhat
Redhat build Of Keycloak
CPE cpe:2.3:a:redhat:build_of_keycloak:26.2:*:*:*:text-only:*:*:*
cpe:2.3:a:redhat:build_of_keycloak:26.4:*:*:*:text-only:*:*:*
cpe:2.3:a:redhat:build_of_keycloak:26.2.15:*:*:*:text-only:*:*:*
cpe:2.3:a:redhat:build_of_keycloak:-:*:*:*:text-only:*:*:*
cpe:2.3:a:redhat:build_of_keycloak:26.4.11:*:*:*:text-only:*:*:*
References () https://access.redhat.com/errata/RHSA-2026:6475 - () https://access.redhat.com/errata/RHSA-2026:6475 - Vendor Advisory
References () https://access.redhat.com/errata/RHSA-2026:6476 - () https://access.redhat.com/errata/RHSA-2026:6476 - Vendor Advisory
References () https://access.redhat.com/errata/RHSA-2026:6477 - () https://access.redhat.com/errata/RHSA-2026:6477 - Vendor Advisory
References () https://access.redhat.com/errata/RHSA-2026:6478 - () https://access.redhat.com/errata/RHSA-2026:6478 - Vendor Advisory
References () https://access.redhat.com/security/cve/CVE-2026-4634 - () https://access.redhat.com/security/cve/CVE-2026-4634 - Vendor Advisory
References () https://bugzilla.redhat.com/show_bug.cgi?id=2450250 - () https://bugzilla.redhat.com/show_bug.cgi?id=2450250 - Issue Tracking, Vendor Advisory

02 Apr 2026, 17:16

Type Values Removed Values Added
References
  • () https://access.redhat.com/errata/RHSA-2026:6475 -
  • () https://access.redhat.com/errata/RHSA-2026:6476 -

02 Apr 2026, 14:16

Type Values Removed Values Added
References
  • () https://access.redhat.com/errata/RHSA-2026:6477 -
  • () https://access.redhat.com/errata/RHSA-2026:6478 -

02 Apr 2026, 13:16

Type Values Removed Values Added
New CVE
Information

Published : 2026-04-02 13:16

Updated : 2026-04-16 20:50

NVD link : CVE-2026-4634

Mitre link : CVE-2026-4634

CVE.ORG link : CVE-2026-4634

JSON object : View

Products Affected

redhat

  • build_of_keycloak
CWE
CWE-1050

Excessive Platform Resource Consumption within a Loop