CVE-2026-9803
MEDIUM EPSS 33.4%
Published May 28, 20261mo ago · Modified Jun 17, 20261w ago
5.3 CVSS 3.1
Published May 28, 2026 1mo ago
Last Modified Jun 17, 2026 1w ago
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.
CVSS Details
Base Score
Exploitability
Impact
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality None
Integrity None
Availability Low
Threat Intelligence
EPSS Exploit Probability
33.4% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available
Weaknesses 1
CWE-125 Out-of-bounds Read Memory Safety
Affected Products 1
| Vendor | Product | Version | Range |
|---|---|---|---|
| redhat | build_of_keycloak | * | any |
References 4
- access.redhat.com https://access.redhat.com/errata/RHSA-2026:25097
- access.redhat.com https://access.redhat.com/errata/RHSA-2026:25098
- access.redhat.com https://access.redhat.com/security/cve/CVE-2026-9803
- bugzilla.redhat.com https://bugzilla.redhat.com/show_bug.cgi?id=2482465
Remediation
No remediation data recorded yet
Check vendor advisories and the NVD entry for patch availability.