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VULNERABILITIES

CVE-2026-9803 Details

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.

Metrics

CVSS 3.x Severity and Vector Strings:

CNA: [email protected]CVSS-B:5.3 MEDIUMVector:CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

References to Advisories, Solutions, and Tools

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URLSource(s)Tag(s)
https://access.redhat.com/errata/RHSA-2026:25097 [email protected]
https://access.redhat.com/errata/RHSA-2026:25098 [email protected]
https://access.redhat.com/errata/RHSA-2026:30049 [email protected]
https://access.redhat.com/errata/RHSA-2026:30050 [email protected]
https://access.redhat.com/security/cve/CVE-2026-9803 [email protected]Vendor Advisory

see all 6 references

Weakness Enumeration

CWE-IDCWE NameSource
CWE-125Out-of-bounds Read[email protected]

Affected Products

ProductVersions
redhat build of keycloak
All versions

CPE

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

Remediation

  • No remediation found in references.

Change History

9 change records found show changes

QUICK INFO

CVE Dictionary Entry:
CVE-2026-9803
NVD Published Date:
May 28, 2026
NVD Last Modified:
Jun 26, 2026
Source:
[email protected]
CVE-2026-9803 Details - Not Deferred