CVE-2026-9803

{"id": "CVE-2026-9803", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Secondary", "source": "secalert@redhat.com", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 5.3, "attackVector": "NETWORK", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "LOW", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 1.4, "exploitabilityScore": 3.9}]}, "published": "2026-05-28T06:16:29.750", "references": [{"url": "https://access.redhat.com/security/cve/CVE-2026-9803", "tags": ["Vendor Advisory"], "source": "secalert@redhat.com"}, {"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2482465", "tags": ["Issue Tracking", "Vendor Advisory"], "source": "secalert@redhat.com"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Primary", "source": "secalert@redhat.com", "description": [{"lang": "en", "value": "CWE-125"}]}], "descriptions": [{"lang": "en", "value": "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."}], "lastModified": "2026-06-03T19:28:55.667", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:redhat:build_of_keycloak:-:*:*:*:-:*:*:*", "vulnerable": true, "matchCriteriaId": "E5C930CB-4EAD-497B-A44B-D880F2A1F85B"}], "operator": "OR"}]}], "sourceIdentifier": "secalert@redhat.com"}