Vulnerability · Published Apr 21, 2026 · Assigned by GitHub_M

CVE-2026-26067October: Safe Mode Bypass via CSS Preprocessor Compilers

Medium 4.9

In plain English

A medium-severity incorrect authorization in october from octobercms. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 16% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)4.9Medium

Exploit odds (30 days)0.2%top 84.1% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Packagist	october/system	3.7.14	GHSA-3888-q23f-x7qh
Packagist	october/system	4.1.10	GHSA-3888-q23f-x7qh

Affected products (as reported)

Vendor	Product	Versions
octobercms	october	>= 4.0.0, < 4.1.10< 3.7.14

Weakness: CWE-863, CWE-184 · Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N

References

https://github.com/octobercms/october/security/advisories/GHSA-3888-q23f-x7qh x_refsource_CONFIRM