CVE-2026-77139: Path Traversal in extension "Mask" (mask)
Vulnerability summary
CVE-2026-77139 is a medium (CVSS 6.0) vulnerability in typo3 extension "mask". EPSS estimates a 0.44% chance of exploitation in the next 30 days, higher than 38% of scored vulnerabilities.
Not severe (CVSS 6, network access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Timeline
- 25-08-2026PublishedVulnerability first disclosed.
- 25-08-2026Last modifiedVulnerability information updated.
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.
CVSS metrics
2 scores · 2 sources · 1 version- NVDNIST6.0MediumCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS trend
Probability
0.44%
Chance of exploitation in the next 30 days
Percentile
38%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.44% on 04-10-2026
Known exploited
Compare KEV catalogsNot in the CISA KEV catalog.
Not in the ENISA CNW catalog.
Not in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-22Improper Limitation of a Pathname to a Restricted DirectoryThe product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.
- CWE-73External Control of File Name or PathThe product allows user input to control or influence paths or file names that are used in filesystem operations.
Affected systems
Known conditions: network-reachable, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Typo31 product
- extension "mask"≥ 9.0.0, < 9.0.11 | < 8.3.12
1 vendor · 1 product
References
1 links- typo3.org/security/advisory/typo3-ext-sa-2026-017Vendor Advisory