Vulnerability · Published Aug 25, 2026 · Assigned by TYPO3

CVE-2026-77139Path Traversal in extension "Mask" (mask)

Medium 6.0

In plain English

A medium-severity path traversal in Extension "Mask" from TYPO3. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 38% of all known vulnerabilities).

Severity (CVSS 4.0)6.0Medium

Exploit odds (30 days)0.4%top 61.9% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

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.

Affected products (as reported)

Vendor	Product	Versions
TYPO3	Extension "Mask"	9.0.0 – before 9.0.110 – before 8.3.12

Weakness: CWE-22, CWE-73 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N

References

https://typo3.org/security/advisory/typo3-ext-sa-2026-017 vendor-advisory