{"id":"CVE-2026-26067","aliases":["EUVD-2026-24153","GHSA-3888-q23f-x7qh"],"status":"published","title":"October: Safe Mode Bypass via CSS Preprocessor Compilers","description":"October is a Content Management System (CMS) and web platform. Prior to 3.7.14 and 4.1.10, a server-side information disclosure vulnerability was identified in the handling of CSS preprocessor files. Backend users with Editor permissions could craft .less, .sass, or .scss files that leverage the compiler's import functionality to read arbitrary files from the server. This worked even with cms.safe_mode enabled. This vulnerability is fixed in 3.7.14 and 4.1.10.","severity":{"version":"3.1","score":4.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00246,"percentile":0.15893,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-184","CWE-200","CWE-22","CWE-863"],"published":"2026-04-21T16:16:03Z","modified":"2026-10-26T22:10:00Z","fixes":[{"ecosystem":"Packagist","package":"october/system","fixed_in":["3.7.14","4.1.10"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"Packagist","package":"october/system","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.7.14"}]}]},{"source":"ghsa","ecosystem":"Packagist","package":"october/system","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.0.0"},{"fixed":"4.1.10"}]}]},{"source":"osv","ecosystem":"Packagist","package":"october/system","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.7.14"}]}],"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","v1.0.472","v1.0.473","v1.0.474","v1.0.475","v1.0.476","v1.1.0","v1.1.1","v1.1.10","v1.1.11","v1.1.12","v1.1.2","v1.1.3","v1.1.4","v1.1.5","v1.1.6","v1.1.9"]},{"source":"osv","ecosystem":"Packagist","package":"october/system","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.0.0"},{"fixed":"4.1.10"}]}]}],"products":[{"vendor":"octobercms","product":"october"}],"references":[{"url":"https://github.com/octobercms/october/security/advisories/GHSA-3888-q23f-x7qh","tags":["x_refsource_CONFIRM","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-26067","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-3888-q23f-x7qh"},{"url":"https://github.com/octobercms/october","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2026-26067","title":"October: Safe Mode Bypass via CSS Preprocessor Compilers","description":"October is a Content Management System (CMS) and web platform. Prior to 3.7.14 and 4.1.10, a server-side information disclosure vulnerability was identified in the handling of CSS preprocessor files. Backend users with Editor permissions could craft .less, .sass, or .scss files that leverage the compiler's import functionality to read arbitrary files from the server. This worked even with cms.safe_mode enabled. This vulnerability is fixed in 3.7.14 and 4.1.10.","status":"published","published":"2026-04-21T16:16:03.293Z","modified":"2026-04-21T17:35:19.882Z","cvss":[{"version":"3.1","score":4.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-863","CWE-184"],"updated_at":"2026-11-02T13:38:20.971157Z"}],"euvd":[{"id":"EUVD-2026-24153","description":"October is a Content Management System (CMS) and web platform. Prior to 3.7.14 and 4.1.10, a server-side information disclosure vulnerability was identified in the handling of CSS preprocessor files. Backend users with Editor permissions could craft .less, .sass, or .scss files that leverage the compiler's import functionality to read arbitrary files from the server. This worked even with cms.safe_mode enabled. This vulnerability is fixed in 3.7.14 and 4.1.10.","status":"published","published":"2026-04-21T16:16:03Z","modified":"2026-04-21T17:35:19Z","cvss":[{"version":"3.1","score":4.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N","level":"medium"}],"updated_at":"2026-11-02T19:24:21.512647Z"}],"ghsa":[{"id":"GHSA-3888-q23f-x7qh","title":"October CMS has Safe Mode Bypass via CSS Preprocessor Compilers","description":"A server-side information disclosure vulnerability was identified in the handling of CSS preprocessor files. Backend users with Editor permissions could craft `.less`, `.sass`, or `.scss` files that leverage the compiler's import functionality to read arbitrary files from the server. This worked even with `cms.safe_mode` enabled.\n\n### Impact\n- Potential exposure of sensitive server-side files\n- Requires authenticated backend access with Editor permissions\n- Only relevant when `cms.safe_mode` is enabled (otherwise direct PHP injection is already possible)\n\n### Patches\nThe vulnerability has been patched in v3.7.14 and v4.1.10. When `cms.safe_mode` is enabled, `.less`, `.sass`, and `.scss` files can no longer be created, uploaded, or edited across the CMS editor, media manager, and file upload interfaces. All users are encouraged to upgrade to the latest patched version.\n\n### Workarounds\nIf upgrading immediately is not possible:\n- Set `cms.editable_asset_types` config to `['css', 'js']` to remove preprocessor file types from the editor\n- Restrict Editor tool access to fully trusted administrators only\n\n- Reported by [Chris Alupului](https://github.com/neosprings)","status":"published","published":"2026-04-21T16:43:49Z","modified":"2026-04-24T21:06:49Z","cvss":[{"version":"3.1","score":4.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N","level":"medium"}],"cwes":["CWE-22","CWE-184","CWE-200"],"updated_at":"2026-11-02T14:39:58.897998Z"}],"nvd":[{"id":"CVE-2026-26067","description":"October is a Content Management System (CMS) and web platform. Prior to 3.7.14 and 4.1.10, a server-side information disclosure vulnerability was identified in the handling of CSS preprocessor files. Backend users with Editor permissions could craft .less, .sass, or .scss files that leverage the compiler's import functionality to read arbitrary files from the server. This worked even with cms.safe_mode enabled. This vulnerability is fixed in 3.7.14 and 4.1.10.","status":"published","published":"2026-04-21T17:16:24.383Z","modified":"2026-10-26T22:10:00.163Z","cvss":[{"version":"3.1","score":4.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N","level":"medium","assessor":"secondary"}],"cwes":["CWE-184","CWE-863"],"updated_at":"2026-11-02T14:12:15.493943Z"}],"osv":[{"id":"GHSA-3888-q23f-x7qh","title":"October CMS has Safe Mode Bypass via CSS Preprocessor Compilers","description":"A server-side information disclosure vulnerability was identified in the handling of CSS preprocessor files. Backend users with Editor permissions could craft `.less`, `.sass`, or `.scss` files that leverage the compiler's import functionality to read arbitrary files from the server. This worked even with `cms.safe_mode` enabled.\n\n### Impact\n- Potential exposure of sensitive server-side files\n- Requires authenticated backend access with Editor permissions\n- Only relevant when `cms.safe_mode` is enabled (otherwise direct PHP injection is already possible)\n\n### Patches\nThe vulnerability has been patched in v3.7.14 and v4.1.10. When `cms.safe_mode` is enabled, `.less`, `.sass`, and `.scss` files can no longer be created, uploaded, or edited across the CMS editor, media manager, and file upload interfaces. All users are encouraged to upgrade to the latest patched version.\n\n### Workarounds\nIf upgrading immediately is not possible:\n- Set `cms.editable_asset_types` config to `['css', 'js']` to remove preprocessor file types from the editor\n- Restrict Editor tool access to fully trusted administrators only\n\n- Reported by [Chris Alupului](https://github.com/neosprings)","status":"published","published":"2026-04-21T16:43:49Z","modified":"2026-05-05T15:59:59.427971Z","cvss":[{"version":"3.1","score":4.9,"vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N","level":"medium"}],"cwes":["CWE-184","CWE-200","CWE-22"],"updated_at":"2026-11-02T15:46:35.406455Z"}]}}