Bug 2482465 (CVE-2026-9803) - CVE-2026-9803 keycloak: Keycloak: Denial of Service via malformed Authorization header
Summary: CVE-2026-9803 keycloak: Keycloak: Denial of Service via malformed Authorizati...
Keywords:
Status: NEW
Alias: CVE-2026-9803
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
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Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-05-28 04:08 UTC by OSIDB Bzimport
Modified: 2026-05-28 04:42 UTC (History)
10 users (show)

Fixed In Version:
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Description OSIDB Bzimport 2026-05-28 04:08:00 UTC 
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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