medium5.3
CVE-2026-9803
A flaw was found in Keycloak's ClientRegistrationAuth component.
Impact
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 packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| maven | org.keycloak:keycloak-services | <= 26.4.7 | none recorded |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Redhat | Build Of Keycloak | All versions |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-cpf7-j4cf-vqx4
- https://nvd.nist.gov/vuln/detail/CVE-2026-9803
- https://access.redhat.com/security/cve/CVE-2026-9803
- https://bugzilla.redhat.com/show_bug.cgi?id=2482465
- https://access.redhat.com/errata/RHSA-2026:25098
- https://access.redhat.com/errata/RHSA-2026:25097
- https://access.redhat.com/errata/RHSA-2026:30049
- https://access.redhat.com/errata/RHSA-2026:30050
- https://github.com/keycloak/keycloak/issues/49433
- https://github.com/keycloak/keycloak/pull/49500
- https://github.com/keycloak/keycloak/pull/49617
- https://github.com/keycloak/keycloak/pull/49618
- https://github.com/keycloak/keycloak/commit/2b8692499e907e6205be0bd9c8a4da5d46f6ca30
- https://github.com/keycloak/keycloak/commit/3fc06909cc93eb5c4739a712fa350de625812e04
- https://github.com/keycloak/keycloak/commit/ef06df91d344c7e99fcb82987ef6adb854f30789