{"id":"GHSA-3jp4-mhh4-gcgr","summary":"Kimai has an Open Redirect via Unvalidated RelayState in SAML ACS Handler","details":"### Summary\n\nThe SAML authentication success handler in Kimai returns the `RelayState` POST parameter as a redirect destination without validating the host or scheme. After a user successfully authenticates via SAML, they are redirected to an attacker-controlled URL if the IdP includes a malicious `RelayState` value. This enables phishing attacks that steal credentials or session tokens post-SSO.\n\n*Requires SAML to be enabled (non-default configuration).*\n\n### Details\n\nVulnerable file: `src/Saml/Security/SamlAuthenticationSuccessHandler.php`\n\n```php\n// Line 27-33\n$relayState = $request-\u003erequest-\u003eget('RelayState', $request-\u003equery-\u003eget('RelayState'));\nif (\\is_scalar($relayState)) {\n    $relayState = (string) $relayState;\n    if ($relayState !== $this-\u003ehttpUtils-\u003egenerateUri($request, (string) $this-\u003eoptions['login_path'])) {\n        return $relayState;  // No host/scheme validation — any URL accepted\n    }\n}\n```\n\nThe only check is that `RelayState` does not equal the configured `login_path`. Any external URL (e.g., `https://attacker.com`) passes this check and is returned as the redirect destination.\n\nThe existing unit test `SamlAuthenticationSuccessHandlerTest::testRelayState()` confirms this behavior — an absolute URL in `RelayState` results in a redirect to that URL with no restriction.\n\n### Steps to Reproduce\n\n```\n1. Enable SAML authentication in Kimai\n2. Configure a SAML IdP (e.g., SimpleSAMLphp)\n3. Initiate IdP-initiated SSO with RelayState=https://attacker.com\n   — or intercept the ACS POST and modify RelayState to https://attacker.com\n4. Complete SAML authentication at the IdP\n5. Observe: after the SAMLResponse POST to /saml/acs, Kimai issues:\n   HTTP/1.1 302 Found\n   Location: https://attacker.com\n```\n\nCode-confirmed via unit test (`testRelayState`): `onAuthenticationSuccess` with `RelayState=http://localhost/relayed` redirects directly to that URL. External URLs follow the same code path.\n\n### Impact\n\nWhile this bug exists it has low practical possibilities and the attacker needs to be able to create a SAML request, meaning either admin access to an IdP supporting such an action OR access to the private SAML keys / certificates.\n\nIn other words: only exploitable in IdP-initiated SSO flows where the IdP includes a `RelayState` value supplied by the attacker (e.g., via a malicious link to the IdP).\n\n### Fix\n\nThe `RelayState` is validated before redirecting, see #5878\n\n- It may not contain a host or port and cannot start with `//`. \n- If it contains a host, it must match the current host.","aliases":["CVE-2026-80200"],"modified":"2026-08-27T04:10:43.335920908Z","published":"2026-04-14T01:06:06Z","database_specific":{"severity":"LOW","github_reviewed":true,"github_reviewed_at":"2026-04-14T01:06:06Z","nvd_published_at":null,"cwe_ids":["CWE-601"]},"references":[{"type":"WEB","url":"https://github.com/kimai/kimai/security/advisories/GHSA-3jp4-mhh4-gcgr"},{"type":"WEB","url":"https://github.com/kimai/kimai/pull/5878"},{"type":"PACKAGE","url":"https://github.com/kimai/kimai"}],"affected":[{"package":{"name":"kimai/kimai","ecosystem":"Packagist","purl":"pkg:composer/kimai/kimai"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.53.0"}]}],"versions":["0.1","0.2","0.3","0.4","0.5","0.6","0.6.1","0.7","0.8","0.8.1","0.9","1.0","1.0.1","1.1","1.10","1.10.1","1.10.2","1.11","1.11.1","1.12","1.13","1.14","1.14.1","1.14.2","1.14.3","1.15","1.15.1","1.15.2","1.15.3","1.15.4","1.15.5","1.15.6","1.16","1.16.1","1.16.10","1.16.2","1.16.3","1.16.4","1.16.5","1.16.6","1.16.7","1.16.8","1.16.9","1.17","1.17.1","1.18","1.18.1","1.18.2","1.19","1.19.1","1.19.2","1.19.3","1.19.4","1.19.5","1.19.6","1.19.7","1.2","1.20","1.20.1","1.20.2","1.20.3","1.20.4","1.21.0","1.22.0","1.22.1","1.23.0","1.23.1","1.24.0","1.25.0","1.26.0","1.27.0","1.28.0","1.28.1","1.29.0","1.29.1","1.3","1.30.0","1.30.1","1.30.10","1.30.11","1.30.2","1.30.3","1.30.4","1.30.5","1.30.6","1.30.7","1.30.8","1.30.9","1.4","1.4.1","1.4.2","1.5","1.6","1.6.1","1.6.2","1.7","1.8","1.9","2.0.0","2.0.0-alpha","2.0.0-beta","2.0.0-beta-2","2.0.0-beta-3","2.0.0-rc-1","2.0.1","2.0.10","2.0.11","2.0.12","2.0.13","2.0.14","2.0.15","2.0.16","2.0.17","2.0.18","2.0.19","2.0.2","2.0.20","2.0.21","2.0.22","2.0.23","2.0.24","2.0.25","2.0.26","2.0.27","2.0.28","2.0.29","2.0.3","2.0.30","2.0.31","2.0.32","2.0.33","2.0.34","2.0.35","2.0.4","2.0.5","2.0.6","2.0.7","2.0.8","2.0.9","2.1.0","2.10.0","2.11.0","2.12.0","2.13.0","2.14.0","2.15.0","2.16.0","2.16.1","2.17.0","2.18.0","2.19.0","2.19.1","2.2.0","2.2.1","2.20.0","2.20.1","2.21.0","2.22.0","2.23.0","2.24.0","2.25.0","2.26.0","2.27.0","2.28.0","2.29.0","2.3.0","2.30.0","2.31.0","2.32.0","2.33.0","2.34.0","2.35.0","2.35.1","2.36.0","2.36.1","2.37.0","2.38.0","2.39.0","2.4.0","2.4.1","2.40.0","2.41.0","2.42.0","2.43.0","2.44.0","2.45.0","2.46.0","2.47.0","2.48.0","2.49.0","2.5.0","2.50.0","2.51.0","2.52.0","2.6.0","2.7.0","2.8.0","2.9.0"],"database_specific":{"last_known_affected_version_range":"\u003c= 2.52.0","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/04/GHSA-3jp4-mhh4-gcgr/GHSA-3jp4-mhh4-gcgr.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:N/A:N"}]}