Is CVE-2026-4634 actively exploited?

CVE-2026-4634 has no public evidence of in-the-wild exploitation as of 2026-04-16.

What is the CVSS score for CVE-2026-4634?

CVE-2026-4634 has a CVSS score of 7.5 (HIGH severity). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

How do I patch CVE-2026-4634?

Patch guidance is available from redhat security advisories. CVEDatabase generates AI-assisted remediation guidance on demand for CVE-2026-4634.

Fix CVE-2026-4634 - HIGH redhat build of keycloak

Q: Which products are affected by CVE-2026-4634?

5 products: redhat build of keycloak, redhat build of keycloak, redhat build of keycloak, redhat build of keycloak, redhat build of keycloak.

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.

CVSS Metrics

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack Vector: network
Complexity: low
Privileges: none
User Action: none
Scope: unchanged
Confidentiality: none
Integrity: none
Availability: high
Weaknesses: CWE-1050

Metadata

Primary Vendor: REDHAT
Published: 4/2/2026
Last Modified: 4/16/2026
Source: NIST NVD
Note: Verify all details with official vendor sources before applying patches.

Affected Products

redhat : build_of_keycloakredhat : build_of_keycloakredhat : build_of_keycloakredhat : build_of_keycloakredhat : build_of_keycloak

Remediation Guidance

Executive Summary

View on NIST NVD