{"id":"CVE-2021-29487","aliases":["GHSA-h76r-vgf3-j6w5"],"url":"https://o3.security/vulnerability/CVE-2021-29487","summary":"October CMS auth bypass and account takeover","details":"### Impact\n\nAn attacker can exploit this vulnerability to bypass authentication using a specially crafted persist cookie.\n\n- To exploit this vulnerability, an attacker must obtain a Laravel’s secret key for cookie encryption and signing.\n- Due to the logic of how this mechanism works, a targeted user account must be logged in while\nthe attacker is exploiting the vulnerability.\n- Authorization via persist cookie not shown in access logs.\n\n### Patches\n\n- Issue has been patched in Build 472 and v1.1.5\n- [Shortened patch instructions](https://github.com/daftspunk/CVE-2021-32648)\n\n### Workarounds\n\nApply https://github.com/octobercms/library/commit/016a297b1bec55d2e53bc889458ed2cb5c3e9374 and https://github.com/octobercms/library/commit/5bd1a28140b825baebe6becd4f7562299d3de3b9 to your installation manually if you are unable to upgrade.\n\n[**Update 2022-01-20**] [Shortened patch instructions](https://github.com/daftspunk/CVE-2021-32648) can be found here.\n\n### Recommendations\n\nWe recommend the following steps to make sure your server stays secure:\n\n- Keep server OS and system software up to date.\n- Keep October CMS software up to date.\n- Use a multi-factor authentication plugin.\n- Change the [default backend URL](https://github.com/octobercms/october/blob/1.1/config/cms.php#L39) or block public access to the backend area.\n- Include the [Roave/SecurityAdvisories](https://github.com/Roave/SecurityAdvisories) Composer package to ensure that your application doesn't have installed dependencies with known security vulnerabilities.\n\n### References\n\nBugs found as part of Solar Security CMS Research. Credits to:\n• Andrey Basarygin\n• Andrey Guzei\n• Mikhail Khramenkov\n• Alexander Sidukov\n• Maxim Teplykh\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","published":"2021-08-26T19:15:07.160Z","modified":"2026-09-22T08:11:25.299878Z","cvss":{"score":7.4,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Packagist","name":"october/system","fixedVersion":"1.0.472"},{"ecosystem":"Packagist","name":"october/system","fixedVersion":"1.1.5"}],"fix":{"url":"https://github.com/octobercms/library/commit/016a297b1bec55d2e53bc889458ed2cb5c3e9374","label":"octobercms/library@016a297"},"references":[{"type":"FIX","url":"https://github.com/octobercms/library/commit/016a297b1bec55d2e53bc889458ed2cb5c3e9374"},{"type":"FIX","url":"https://github.com/octobercms/library/commit/5bd1a28140b825baebe6becd4f7562299d3de3b9"},{"type":"FIX","url":"https://github.com/octobercms/october/security/advisories/GHSA-h76r-vgf3-j6w5"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-29487"},{"type":"PACKAGE","url":"https://github.com/octobercms/october"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-09-22T08:11:25.299878Z"}}