GitHub Advisoryadvisory · Maven

GHSA-cpf7-j4cf-vqx4 Keycloak has an Out-of-bounds Read

MEDIUM Published 2026-05-28 Modified 2026-07-01 Official page ↗
Aliases
CVE-2026-9803
Ecosystem
Maven
Packages
org.keycloak:keycloak-services
Severity
Moderate
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weaknesses
CWE-125
Reviewed
2026-07-01

Affected packages

• Maven org.keycloak:keycloak-services: <= 26.4.7 (no fix yet) • Maven org.keycloak:keycloak-services: >= 26.5.0, < 26.6.3 → fixed in 26.6.3

Description

A flaw was found in Keycloak's ClientRegistrationAuth component. A remote unauthenticated attacker can exploit this vulnerability by sending a specially crafted POST request with a malformed 'Authorization: Bearer' header to any client registration endpoint. This can lead to an ArrayIndexOutOfBoundsException, causing the server to return an HTTP 500 error and resulting in a Denial of Service (DoS) for the affected service.

Related

Alias · CVE (1)

  • CVE-2026-9803 A flaw was found in Keycloak's ClientRegistrationAuth component. vulnerability

Weakness · CWE (1)

  • CWE-125 Out-of-bounds Read weakness

References