{"id":"CVE-2021-21264","aliases":["EUVD-2021-1058","GHSA-fcr8-6q7r-m4wg"],"status":"published","title":"Bypass of fix for CVE-2020-26231, Twig sandbox escape","description":"October is a free, open-source, self-hosted CMS platform based on the Laravel PHP Framework. A bypass of CVE-2020-26231 (fixed in 1.0.470/471 and 1.1.1) was discovered that has the same impact as CVE-2020-26231 \u0026 CVE-2020-15247. An authenticated backend user with the `cms.manage_pages`, `cms.manage_layouts`, or `cms.manage_partials` permissions who would **normally** not be permitted to provide PHP code to be executed by the CMS due to `cms.enableSafeMode` being enabled is able to write specific Twig code to escape the Twig sandbox and execute arbitrary PHP. This is not a problem for anyone that trusts their users with those permissions to normally write \u0026 manage PHP within the CMS by not having `cms.enableSafeMode` enabled, but would be a problem for anyone relying on `cms.enableSafeMode` to ensure that users with those permissions in production do not have access to write \u0026 execute arbitrary PHP. Issue has been patched in Build 472 (v1.0.472) and v1.1.2. As a workaround, apply https://github.com/octobercms/october/commit/f63519ff1e8d375df30deba63156a2fc97aa9ee7 to your installation manually if unable to upgrade to Build 472 or v1.1.2.","severity":{"version":"3.1","score":5.2,"vector":"CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:L","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.00265,"percentile":0.18536,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-862"],"published":"2021-05-03T16:00:18Z","modified":"2026-10-20T10:54:27Z","fixes":[{"ecosystem":"Packagist","package":"october/cms","fixed_in":["1.0.472","1.1.2"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"Packagist","package":"october/cms","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.0.471"},{"last_affected":"1.0.471"},{"fixed":"1.0.472"}]}],"versions":["1.0.471"]},{"source":"ghsa","ecosystem":"Packagist","package":"october/cms","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.1.1"},{"last_affected":"1.1.1"},{"fixed":"1.1.2"}]}],"versions":["1.1.1"]},{"source":"osv","ecosystem":"Packagist","package":"october/cms","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.0.471"},{"fixed":"1.0.472"}]}],"versions":["1.0.471","v1.0.471"]},{"source":"osv","ecosystem":"Packagist","package":"october/cms","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.1.1"},{"fixed":"1.1.2"}]}],"versions":["1.1.1","v1.1.1"]}],"products":[{"vendor":"octobercms","product":"october"}],"references":[{"url":"https://github.com/octobercms/october/security/advisories/GHSA-fcr8-6q7r-m4wg","tags":["x_refsource_CONFIRM","x_transferred","Patch","Third Party Advisory","fix","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-21264","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-fcr8-6q7r-m4wg"},{"url":"https://github.com/octobercms/october","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2021-21264","title":"Bypass of fix for CVE-2020-26231, Twig sandbox escape","description":"October is a free, open-source, self-hosted CMS platform based on the Laravel PHP Framework. A bypass of CVE-2020-26231 (fixed in 1.0.470/471 and 1.1.1) was discovered that has the same impact as CVE-2020-26231 \u0026 CVE-2020-15247. An authenticated backend user with the `cms.manage_pages`, `cms.manage_layouts`, or `cms.manage_partials` permissions who would **normally** not be permitted to provide PHP code to be executed by the CMS due to `cms.enableSafeMode` being enabled is able to write specific Twig code to escape the Twig sandbox and execute arbitrary PHP. This is not a problem for anyone that trusts their users with those permissions to normally write \u0026 manage PHP within the CMS by not having `cms.enableSafeMode` enabled, but would be a problem for anyone relying on `cms.enableSafeMode` to ensure that users with those permissions in production do not have access to write \u0026 execute arbitrary PHP. Issue has been patched in Build 472 (v1.0.472) and v1.1.2. As a workaround, apply https://github.com/octobercms/october/commit/f63519ff1e8d375df30deba63156a2fc97aa9ee7 to your installation manually if unable to upgrade to Build 472 or v1.1.2.","status":"published","published":"2021-05-03T16:00:18Z","modified":"2024-08-03T18:09:14.926Z","cvss":[{"version":"3.1","score":5.2,"vector":"CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:L","level":"medium","assessor":"cna"}],"cwes":["CWE-862"],"updated_at":"2026-11-02T14:33:00.137099Z"}],"euvd":[{"id":"EUVD-2021-1058","description":"October is a free, open-source, self-hosted CMS platform based on the Laravel PHP Framework. A bypass of CVE-2020-26231 (fixed in 1.0.470/471 and 1.1.1) was discovered that has the same impact as CVE-2020-26231 \u0026 CVE-2020-15247. An authenticated backend user with the `cms.manage_pages`, `cms.manage_layouts`, or `cms.manage_partials` permissions who would **normally** not be permitted to provide PHP code to be executed by the CMS due to `cms.enableSafeMode` being enabled is able to write specific Twig code to escape the Twig sandbox and execute arbitrary PHP. This is not a problem for anyone that trusts their users with those permissions to normally write \u0026 manage PHP within the CMS by not having `cms.enableSafeMode` enabled, but would be a problem for anyone relying on `cms.enableSafeMode` to ensure that users with those permissions in production do not have access to write \u0026 execute arbitrary PHP. Issue has been patched in Build 472 (v1.0.472) and v1.1.2. As a workaround, apply https://github.com/octobercms/october/commit/f63519ff1e8d375df30deba63156a2fc97aa9ee7 to your installation manually if unable to upgrade to Build 472 or v1.1.2.","status":"published","published":"2021-05-03T16:00:18Z","modified":"2024-08-03T18:09:14Z","cvss":[{"version":"3.1","score":5.2,"vector":"CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:L","level":"medium"}],"updated_at":"2026-11-03T03:25:06.913643Z"}],"ghsa":[{"id":"GHSA-fcr8-6q7r-m4wg","title":"Bypass of fix for CVE-2020-26231, Twig sandbox escape","description":"### Impact\nA bypass of CVE-2020-26231 (fixed in 1.0.470/471 and 1.1.1) was discovered that has the same impact as CVE-2020-26231 \u0026 CVE-2020-15247:\n\nAn authenticated backend user with the `cms.manage_pages`, `cms.manage_layouts`, or `cms.manage_partials` permissions who would **normally** not be permitted to provide PHP code to be executed by the CMS due to `cms.enableSafeMode` being enabled is able to write specific Twig code to escape the Twig sandbox and execute arbitrary PHP.\n\nThis is not a problem for anyone that trusts their users with those permissions to normally write \u0026 manage PHP within the CMS by not having `cms.enableSafeMode` enabled, but would be a problem for anyone relying on `cms.enableSafeMode` to ensure that users with those permissions in production do not have access to write \u0026 execute arbitrary PHP.\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/october/commit/f63519ff1e8d375df30deba63156a2fc97aa9ee7 to your installation manually if unable to upgrade to Build 472 or v1.1.2.\n\n### References\nReported by [ka1n4t](https://github.com/ka1n4t)\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=\"1108\" alt=\"Screen Shot 2020-10-10 at 1 21 13 PM\" src=\"https://user-images.githubusercontent.com/7253840/95663316-7de28b80-0afb-11eb-999d-a6526cf78709.png\"\u003e","status":"published","published":"2021-05-04T17:42:33Z","modified":"2023-02-01T05:05:33Z","cvss":[{"version":"3.1","score":5.2,"vector":"CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:L","level":"medium"}],"cwes":["CWE-862"],"updated_at":"2026-11-02T14:36:34.917834Z"}],"nvd":[{"id":"CVE-2021-21264","description":"October is a free, open-source, self-hosted CMS platform based on the Laravel PHP Framework. A bypass of CVE-2020-26231 (fixed in 1.0.470/471 and 1.1.1) was discovered that has the same impact as CVE-2020-26231 \u0026 CVE-2020-15247. An authenticated backend user with the `cms.manage_pages`, `cms.manage_layouts`, or `cms.manage_partials` permissions who would **normally** not be permitted to provide PHP code to be executed by the CMS due to `cms.enableSafeMode` being enabled is able to write specific Twig code to escape the Twig sandbox and execute arbitrary PHP. This is not a problem for anyone that trusts their users with those permissions to normally write \u0026 manage PHP within the CMS by not having `cms.enableSafeMode` enabled, but would be a problem for anyone relying on `cms.enableSafeMode` to ensure that users with those permissions in production do not have access to write \u0026 execute arbitrary PHP. Issue has been patched in Build 472 (v1.0.472) and v1.1.2. As a workaround, apply https://github.com/octobercms/october/commit/f63519ff1e8d375df30deba63156a2fc97aa9ee7 to your installation manually if unable to upgrade to Build 472 or v1.1.2.","status":"published","published":"2021-05-03T16:15:07.51Z","modified":"2026-06-17T03:35:09.167Z","cvss":[{"version":"3.1","score":5.2,"vector":"CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:L","level":"medium","assessor":"secondary"},{"version":"3.1","score":5.2,"vector":"CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:L","level":"medium","assessor":"primary"},{"version":"2.0","score":4.4,"vector":"AV:L/AC:M/Au:N/C:P/I:P/A:P","level":"medium","assessor":"primary"}],"cwes":["CWE-862"],"updated_at":"2026-11-02T14:06:52.81233Z"}],"osv":[{"id":"CVE-2021-21264","description":"October is a free, open-source, self-hosted CMS platform based on the Laravel PHP Framework. A bypass of CVE-2020-26231 (fixed in 1.0.470/471 and 1.1.1) was discovered that has the same impact as CVE-2020-26231 \u0026 CVE-2020-15247. An authenticated backend user with the `cms.manage_pages`, `cms.manage_layouts`, or `cms.manage_partials` permissions who would **normally** not be permitted to provide PHP code to be executed by the CMS due to `cms.enableSafeMode` being enabled is able to write specific Twig code to escape the Twig sandbox and execute arbitrary PHP. This is not a problem for anyone that trusts their users with those permissions to normally write \u0026 manage PHP within the CMS by not having `cms.enableSafeMode` enabled, but would be a problem for anyone relying on `cms.enableSafeMode` to ensure that users with those permissions in production do not have access to write \u0026 execute arbitrary PHP. Issue has been patched in Build 472 (v1.0.472) and v1.1.2. As a workaround, apply https://github.com/octobercms/october/commit/f63519ff1e8d375df30deba63156a2fc97aa9ee7 to your installation manually if unable to upgrade to Build 472 or v1.1.2.","status":"published","published":"2021-05-03T16:15:07.51Z","modified":"2026-10-20T10:54:27.818704764Z","cvss":[{"version":"3.1","score":5.2,"vector":"CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:L","level":"medium"}],"updated_at":"2026-11-02T15:44:18.004149Z"},{"id":"GHSA-fcr8-6q7r-m4wg","title":"Bypass of fix for CVE-2020-26231, Twig sandbox escape","description":"### Impact\nA bypass of CVE-2020-26231 (fixed in 1.0.470/471 and 1.1.1) was discovered that has the same impact as CVE-2020-26231 \u0026 CVE-2020-15247:\n\nAn authenticated backend user with the `cms.manage_pages`, `cms.manage_layouts`, or `cms.manage_partials` permissions who would **normally** not be permitted to provide PHP code to be executed by the CMS due to `cms.enableSafeMode` being enabled is able to write specific Twig code to escape the Twig sandbox and execute arbitrary PHP.\n\nThis is not a problem for anyone that trusts their users with those permissions to normally write \u0026 manage PHP within the CMS by not having `cms.enableSafeMode` enabled, but would be a problem for anyone relying on `cms.enableSafeMode` to ensure that users with those permissions in production do not have access to write \u0026 execute arbitrary PHP.\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/october/commit/f63519ff1e8d375df30deba63156a2fc97aa9ee7 to your installation manually if unable to upgrade to Build 472 or v1.1.2.\n\n### References\nReported by [ka1n4t](https://github.com/ka1n4t)\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=\"1108\" alt=\"Screen Shot 2020-10-10 at 1 21 13 PM\" src=\"https://user-images.githubusercontent.com/7253840/95663316-7de28b80-0afb-11eb-999d-a6526cf78709.png\"\u003e","status":"published","published":"2021-05-04T17:42:33Z","modified":"2026-07-08T06:30:01.387714458Z","cvss":[{"version":"3.1","score":5.2,"vector":"CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:L","level":"medium"}],"cwes":["CWE-862"],"updated_at":"2026-11-02T15:46:46.39441Z"}]}}