CVE-2026-77139 Path Traversal in extension "Mask" (mask)
Authenticated backend users can exploit path traversal in the Mask extension to create or delete HTML files outside the intended template directory.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-77139?
CVE-2026-77139 is a medium-severity path traversal vulnerability in TYPO3 Extension "Mask", published on 25 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
The extension fails to validate a client-supplied template element key before using it to build file paths for saving and deleting Mask template files. An authenticated backend user with access to the Mask module can supply a key containing path traversal sequences to create or delete .html files outside the configured template directory.
Which versions are affected by CVE-2026-77139?
How do I fix CVE-2026-77139?
No fix has been published for CVE-2026-77139 yet. Limit exposure of the affected software until one is available.
Upgrade, and resolve every user-supplied path against an allowed base folder before opening it. More about Path traversal.
Is CVE-2026-77139 being exploited?
There is no known exploitation of CVE-2026-77139 in the wild and no public exploit code.
Sources
Also known as GHSA-q7c6-98mw-7m48.