{"id":"CVE-2021-3311","aliases":["EUVD-2021-0537","GHSA-7ggw-h8pp-r95r"],"status":"published","title":"October CMS Session ID not invalidated after logout","description":"An issue was discovered in October through build 471. It reactivates an old session ID (which had been invalid after a logout) once a new login occurs. NOTE: this violates the intended Auth/Manager.php authentication behavior but, admittedly, is only relevant if an old session ID is known to an attacker.","severity":{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-09","score":0.02963,"percentile":0.87316,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-613"],"published":"2021-02-05T04:47:53Z","modified":"2026-10-24T10:50:41Z","fixes":[{"ecosystem":"Packagist","package":"october/rain","fixed_in":["1.0.472","1.1.2"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"Packagist","package":"october/rain","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.0.472"}]}]},{"source":"ghsa","ecosystem":"Packagist","package":"october/rain","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.1.0"},{"fixed":"1.1.2"}]}]},{"source":"osv","ecosystem":"Packagist","package":"october/rain","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.0.472"}]}],"versions":["v1.0.319","v1.0.320","v1.0.321","v1.0.322","v1.0.323","v1.0.324","v1.0.325","v1.0.326","v1.0.327","v1.0.328","v1.0.329","v1.0.330","v1.0.331","v1.0.332","v1.0.333","v1.0.334","v1.0.335","v1.0.336","v1.0.337","v1.0.338","v1.0.339","v1.0.340","v1.0.341","v1.0.342","v1.0.343","v1.0.344","v1.0.345","v1.0.346","v1.0.347","v1.0.348","v1.0.349","v1.0.350","v1.0.351","v1.0.352","v1.0.353","v1.0.354","v1.0.355","v1.0.356","v1.0.357","v1.0.358","v1.0.359","v1.0.360","v1.0.361","v1.0.362","v1.0.363","v1.0.364","v1.0.365","v1.0.366","v1.0.367","v1.0.368","v1.0.369","v1.0.370","v1.0.371","v1.0.372","v1.0.373","v1.0.374","v1.0.375","v1.0.376","v1.0.377","v1.0.378","v1.0.379","v1.0.380","v1.0.381","v1.0.382","v1.0.383","v1.0.384","v1.0.385","v1.0.386","v1.0.387","v1.0.388","v1.0.389","v1.0.390","v1.0.391","v1.0.392","v1.0.393","v1.0.394","v1.0.395","v1.0.396","v1.0.397","v1.0.398","v1.0.399","v1.0.400","v1.0.401","v1.0.402","v1.0.403","v1.0.404","v1.0.405","v1.0.406","v1.0.407","v1.0.408","v1.0.409","v1.0.410","v1.0.411","v1.0.412","v1.0.413","v1.0.414","v1.0.415","v1.0.416","v1.0.417","v1.0.418","v1.0.419","v1.0.420","v1.0.421","v1.0.422","v1.0.423","v1.0.424","v1.0.425","v1.0.426","v1.0.427","v1.0.428","v1.0.429","v1.0.430","v1.0.431","v1.0.432","v1.0.433","v1.0.434","v1.0.435","v1.0.436","v1.0.437","v1.0.438","v1.0.439","v1.0.440","v1.0.441","v1.0.442","v1.0.443","v1.0.444","v1.0.445","v1.0.446","v1.0.447","v1.0.448","v1.0.449","v1.0.450","v1.0.451","v1.0.452","v1.0.453","v1.0.454","v1.0.455","v1.0.456","v1.0.457","v1.0.458","v1.0.459","v1.0.460","v1.0.461","v1.0.462","v1.0.463","v1.0.464","v1.0.465","v1.0.466","v1.0.467","v1.0.468","v1.0.469","v1.0.470","v1.0.471"]},{"source":"osv","ecosystem":"Packagist","package":"october/rain","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.1.0"},{"fixed":"1.1.2"}]}],"versions":["v1.1.0","v1.1.1"]}],"products":[{"vendor":"octobercms","product":"october"}],"references":[{"url":"https://octobercms.com/forum/chan/announcements","tags":["x_refsource_MISC","x_transferred","Vendor Advisory","advisory","web"]},{"url":"https://github.com/octobercms/library/commit/642f597489e6f644d4bd9a0c267e864cabead024","tags":["x_refsource_CONFIRM","x_transferred","Patch","Third Party Advisory","fix","web"]},{"url":"https://anisiosantos.me/october-cms-token-reactivation","tags":["x_refsource_MISC","x_transferred","Exploit","Third Party Advisory","evidence","web"]},{"url":"https://github.com/octobercms/october/security/advisories/GHSA-7ggw-h8pp-r95r","tags":["web"]},{"url":"https://packagist.org/packages/october/rain","tags":["web"]},{"url":"http://cve.circl.lu/cve/CVE-2021-3311","tags":["web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-3311","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-7ggw-h8pp-r95r"}],"sources":{"cve":[{"id":"CVE-2021-3311","description":"An issue was discovered in October through build 471. It reactivates an old session ID (which had been invalid after a logout) once a new login occurs. NOTE: this violates the intended Auth/Manager.php authentication behavior but, admittedly, is only relevant if an old session ID is known to an attacker.","status":"published","published":"2021-02-05T04:47:53Z","modified":"2024-08-03T16:53:17.588Z","updated_at":"2026-11-02T14:33:04.360272Z"}],"euvd":[{"id":"EUVD-2021-0537","description":"An issue was discovered in October through build 471. It reactivates an old session ID (which had been invalid after a logout) once a new login occurs. NOTE: this violates the intended Auth/Manager.php authentication behavior but, admittedly, is only relevant if an old session ID is known to an attacker.","status":"published","published":"2021-02-05T04:47:53Z","modified":"2024-08-03T16:53:17Z","updated_at":"2026-11-03T03:25:13.531128Z"}],"ghsa":[{"id":"GHSA-7ggw-h8pp-r95r","title":"October CMS Session ID not invalidated after logout","description":"### Impact\nWhen logging out, the session ID was not invalidated. This is not a problem while the user is logged out, but as soon as the user logs back in the old session ID would be valid again; which means that anyone that gained access to the old session cookie would be able to act as the logged in user. This is not a major concern for the majority of cases, since it requires a malicious party gaining access to the session cookie in the first place, but nevertheless has been fixed.\n\n### Patches\nIssue has been patched in Build 472 (v1.0.472) and v1.1.2.\n\n### Workarounds\nApply https://github.com/octobercms/library/commit/642f597489e6f644d4bd9a0c267e864cabead024 to your installation manually if unable to upgrade to Build 472 or v1.1.2.\n\n### References\n- Reported by Anisio (Brazilian Information Security Analyst)\n- http://cve.circl.lu/cve/CVE-2021-3311\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Email us at [hello@octobercms.com](mailto:hello@octobercms.com)\n\n### Threat assessment:\n\u003cimg width=\"699\" alt=\"Screen Shot 2021-02-07 at 11 50 35 PM\" src=\"https://user-images.githubusercontent.com/7253840/107180881-51eaf000-699f-11eb-8828-333128faf2a6.png\"\u003e","status":"published","published":"2021-02-10T02:32:35Z","modified":"2023-09-07T17:47:27Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"cwes":["CWE-613"],"updated_at":"2026-11-02T14:37:02.632342Z"}],"nvd":[{"id":"CVE-2021-3311","description":"An issue was discovered in October through build 471. It reactivates an old session ID (which had been invalid after a logout) once a new login occurs. NOTE: this violates the intended Auth/Manager.php authentication behavior but, admittedly, is only relevant if an old session ID is known to an attacker.","status":"published","published":"2021-02-05T14:15:19.153Z","modified":"2026-06-17T04:04:55.23Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"primary"},{"version":"2.0","score":6.8,"vector":"AV:N/AC:M/Au:N/C:P/I:P/A:P","level":"medium","assessor":"primary"}],"cwes":["CWE-613"],"updated_at":"2026-11-02T14:06:49.660551Z"}],"osv":[{"id":"CVE-2021-3311","description":"An issue was discovered in October through build 471. It reactivates an old session ID (which had been invalid after a logout) once a new login occurs. NOTE: this violates the intended Auth/Manager.php authentication behavior but, admittedly, is only relevant if an old session ID is known to an attacker.","status":"published","published":"2021-02-05T14:15:19.153Z","modified":"2026-10-24T10:50:41.748924368Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"updated_at":"2026-11-02T15:44:19.793849Z"},{"id":"GHSA-7ggw-h8pp-r95r","title":"October CMS Session ID not invalidated after logout","description":"### Impact\nWhen logging out, the session ID was not invalidated. This is not a problem while the user is logged out, but as soon as the user logs back in the old session ID would be valid again; which means that anyone that gained access to the old session cookie would be able to act as the logged in user. This is not a major concern for the majority of cases, since it requires a malicious party gaining access to the session cookie in the first place, but nevertheless has been fixed.\n\n### Patches\nIssue has been patched in Build 472 (v1.0.472) and v1.1.2.\n\n### Workarounds\nApply https://github.com/octobercms/library/commit/642f597489e6f644d4bd9a0c267e864cabead024 to your installation manually if unable to upgrade to Build 472 or v1.1.2.\n\n### References\n- Reported by Anisio (Brazilian Information Security Analyst)\n- http://cve.circl.lu/cve/CVE-2021-3311\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Email us at [hello@octobercms.com](mailto:hello@octobercms.com)\n\n### Threat assessment:\n\u003cimg width=\"699\" alt=\"Screen Shot 2021-02-07 at 11 50 35 PM\" src=\"https://user-images.githubusercontent.com/7253840/107180881-51eaf000-699f-11eb-8828-333128faf2a6.png\"\u003e","status":"published","published":"2021-02-10T02:32:35Z","modified":"2024-02-16T08:20:41.182309Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"cwes":["CWE-613"],"updated_at":"2026-11-02T15:46:41.002603Z"}]}}