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CVE PROGRAM SOURCE RECORD5.3 Medium

CVE-2026-9803

Keycloak: keycloak: denial of service via malformed authorization header

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Status
Published
Published
Updated
Assigning organization
redhat

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.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Red Hat Red Hat build of Keycloak 26.4

Default version status: affected

  • 26.4.13-1 to < *unaffected

Red Hat Red Hat build of Keycloak 26.4

Default version status: affected

  • 26.4-19 to < *unaffected

Red Hat Red Hat build of Keycloak 26.4

Default version status: affected

  • 26.4-19 to < *unaffected

Red Hat Red Hat build of Keycloak 26.4.13

Default version status: unaffected

Red Hat Red Hat build of Keycloak 26.6

Default version status: affected

  • 26.6.3-3 to < *unaffected

Red Hat Red Hat build of Keycloak 26.6

Default version status: affected

  • 26.6-6 to < *unaffected

Red Hat Red Hat build of Keycloak 26.6

Default version status: affected

  • 26.6-6 to < *unaffected

Red Hat Red Hat build of Keycloak 26.6.3

Default version status: unaffected

References