CVE-2026-26067

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.

Workarounds

If upgrading immediately is not possible:

• Set cms.editable_asset_types config to ['css', 'js'] to remove preprocessor file types from the editor

• Restrict Editor tool access to fully trusted administrators only

• Reported by Chris Alupului

• Potential exposure of sensitive server-side files
• Requires authenticated backend access with Editor permissions
• Only relevant when cms.safe_mode is enabled (otherwise direct PHP injection is already possible)

Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files. Typical impact: unauthorized file read or write outside the intended directory.

CVE-2026-26067 has a CVSS score of 4.9 (Medium). The vector is network-reachable, high privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (3.7.14, 4.1.10); upgrading removes the vulnerable code path.

Kodem intelligence

The 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.

1. What is CVE-2026-26067? CVE-2026-26067 is a medium-severity path traversal vulnerability in october/system (composer), affecting versions < 3.7.14. It is fixed in 3.7.14, 4.1.10. Input manipulates file paths to reach files outside the intended directory, such as configuration or credential files.
2. How severe is CVE-2026-26067? CVE-2026-26067 has a CVSS score of 4.9 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of october/system are affected by CVE-2026-26067? october/system (composer) versions < 3.7.14 is affected.
4. Is there a fix for CVE-2026-26067? Yes. CVE-2026-26067 is fixed in 3.7.14, 4.1.10. Upgrade to this version or later.
5. Is CVE-2026-26067 exploitable, and should I be worried? Whether CVE-2026-26067 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-26067 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-26067?
   • Upgrade october/system to 3.7.14 or later
   • Upgrade october/system to 4.1.10 or later