CVE-2026-26067 October: Safe Mode Bypass via CSS Preprocessor Compilers
Editors can bypass safe mode to read arbitrary server files via crafted CSS preprocessor imports in October CMS.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-26067?
CVE-2026-26067 is a medium-severity path traversal vulnerability in octobercms october, published on 21 Apr 2026. An attacker needs administrator access to exploit it, with no action from the victim.
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.
Which versions are affected by CVE-2026-26067?
4 open source packages ship an affected version, including october/system.
| Package | Affected | Fixed in |
|---|---|---|
october/system Packagist | All versions | 3.7.14 |
october/system Packagist | All versions | 3.7.14 |
october/system Packagist | From 4.0.0 | 4.1.10 |
october/system Packagist | From 4.0.0 | 4.1.10 |
How do I fix CVE-2026-26067?
Upgrade october/system to a fixed version for your release line: 3.7.14 or 4.1.10.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-26067 being exploited?
There is no known exploitation of CVE-2026-26067 in the wild and no public exploit code.
Sources
Also known as GHSA-3888-q23f-x7qh.