CVE-2026-9803

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.

CVSS v3 5.3 MEDIUM

5.3^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 3.9 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact LOW

Scope UNCHANGED

References

Link	Resource
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 Tracking Vendor Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:a:redhat:build_of_keycloak:-:*:*:*:-:*:*:*

History

26 Oct 2026, 12:10

Type	Values Removed	Values Added
Summary		(es) Se encontró un fallo en el componente ClientRegistrationAuth de Keycloak. Un atacante remoto no autenticado puede explotar esta vulnerabilidad enviando una solicitud POST especialmente diseñada con una cabecera ’Authorization: Bearer’ malformada a cualquier endpoint de registro de cliente. Esto puede llevar a una ArrayIndexOutOfBoundsException, haciendo que el servidor devuelva un error HTTP 500 y resultando en una Denegación de Servicio (DoS) para el servicio afectado.

Information

Published : 2026-05-28 06:16

Updated : 2026-10-26 12:10

NVD link : CVE-2026-9803

Mitre link : CVE-2026-9803

CVE.ORG link : CVE-2026-9803

JSON object : View

Products Affected

redhat

build_of_keycloak

CWE

CWE-125

Out-of-bounds Read

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