CVE-2026-9803GHSA-CPF7-J4CF-VQX4
Keycloak: keycloak: denial of service via malformed authorization header
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 26.6.3
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
CISA's decision points: whether it is exploited, whether attacks can be automated, and how much control an attacker gets. Assessed (SSVC 2.0.3).What do these mean? →
- Exploitation: none
- Automatable: yes
- Technical impact: partial
Summary
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.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: yes · Technical impact: partial
- Record last updated
Affected versions
- rhbk/keycloak-operator-bundle
Version range not reported
- rhbk/keycloak-rhel9
Version range not reported
- rhbk/keycloak-rhel9-operator
Version range not reported
- rhbk/keycloak-rhel9
Version range not reported
- rhbk/keycloak-operator-bundle
Version range not reported
- rhbk/keycloak-rhel9
Version range not reported
- rhbk/keycloak-rhel9-operator
Version range not reported
- rhbk/keycloak-rhel9
Version range not reported
- org.keycloak:keycloak-servicesMaven
through 26.4.7
- org.keycloak:keycloak-servicesMaven
From 26.5.0 · fixed in 26.6.3