CVSS 4.0
6.3 mediumCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:NCVE-2026-27199
Medium (6.3) in palletsprojects werkzeug. EPSS 0.6% chance of exploitation in the next 30 days. Fixed in werkzeug 3.1.6.
Werkzeug is a comprehensive WSGI web application library. Versions 3.1.5 and below, the safe_join function allows Windows device names as filenames if preceded by other path segments. This was previously reported as GHSA-hgf8-39gv-g3f2, but the added filtering failed to account for the fact that safe_join accepts paths with multiple segments, such as example/NUL. The function send_from_directory uses safe_join to safely serve files at user-specified paths under a directory. If the application is running on Windows, and the requested path ends with a special device name, the file will be opened successfully, but reading will hang indefinitely. This issue has been fixed in version 3.1.6.
Severity
CVSS 3.1
5.3 mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L- EPSS
- 0.6% chance of exploitation in the next 30 days; higher than 50% of CVEs (scores of 2026-10-31)
- CWE
- CWE-67
- Published
- Modified
- Record from
- the NVD, synced
Affected
- palletsprojects:werkzeug
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-29vq-49wr-vm6x | PyPI | werkzeug | <3.1.6 | 3.1.6 |
| PYSEC-2026-2320 | PyPI | werkzeug | <3.1.6 | 3.1.6 |