CVE-2026-9803

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.

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Produits concernés

• Red Hat build of Keycloak 26.4
• Red Hat build of Keycloak 26.4.13
• Red Hat build of Keycloak 26.6
• Red Hat build of Keycloak 26.6.3
• Redhat build of keycloak

Scores CVSS

Faiblesses (CWE)

• CWE-125

Références

• https://access.redhat.com/errata/RHSA-2026:25097
• https://access.redhat.com/errata/RHSA-2026:25098
• https://access.redhat.com/errata/RHSA-2026:30049
• https://access.redhat.com/errata/RHSA-2026:30050
• https://access.redhat.com/security/cve/CVE-2026-9803 Vendor Advisory
• https://bugzilla.redhat.com/show_bug.cgi?id=2482465 Issue TrackingVendor Advisory

Ailleurs

• NVD
• CVE.org
• CIRCL Vulnerability-Lookup
• CERT-FR
• GitHub Advisories