CVE-2026-26067 PUBLISHED

October: Safe Mode Bypass via CSS Preprocessor Compilers

Assigner: GitHub_M
Reserved: 10.02.2026 Published: 21.04.2026 Updated: 21.04.2026

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.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N
CVSS Score: 4.9

Product Status

Vendor octobercms
Product october
Versions
  • Version >= 4.0.0, < 4.1.10 is affected
  • Version < 3.7.14 is affected

References

Problem Types

  • CWE-863: Incorrect Authorization CWE
  • CWE-184: Incomplete List of Disallowed Inputs CWE