CVE-2026-27199Werkzeug is a comprehensive WSGI web application library.
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 5.3 MEDIUM (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- Weakness (CWE)
- CWE-67
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Not given
- NVD analysis
- Analyzed
- Record last updated
- Jun 17, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
palletsprojects werkzeug palletsprojects:werkzeug | before 3.1.6 | NVD |
References
- https://github.com/pallets/werkzeug/commit/f407712fdc60a09c2b3f4fe7db557703e5d9338dpatch
- https://github.com/pallets/werkzeug/releases/tag/3.1.6release-notes
- https://github.com/pallets/werkzeug/security/advisories/GHSA-29vq-49wr-vm6xvendor-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.