CVE catalog
CVE-2026-27199
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 previou
- Severity
- Medium · CVSS 6.3
- Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.63% · Oct 25, 2026
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.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | python-werkzeug | sid | 3.1.9-1 | not affected |
| Debian | python-werkzeug | forky | 3.1.9-1 | not affected |
| Debian | python-werkzeug | trixie | 3.1.3-2 | not affected |
| Debian | python-werkzeug | bookworm | 2.2.2-3+deb12u1 | not affected |
| Pip | werkzeug | Not reported | 3.1.6 | fixed |
| PyPI | werkzeug | Not reported | 3.1.6 | fixed |
| Alpine | py3-werkzeug | 3.24 | 3.1.6-r0 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | python-werkzeug | source | sid | Not affected | unimportant | Not reported | Not reported |
| Debian | python-werkzeug | source | forky | Not affected | unimportant | Not reported | Not reported |
| Debian | python-werkzeug | source | trixie | Not affected | unimportant | Not reported | Not reported |
| Debian | python-werkzeug | source | bookworm | Not affected | unimportant | Not reported | Not reported |
| Pip | werkzeug | pip | Not reported | 3.1.6 | Not reported | Not reported | Not reported |
| PyPI | werkzeug | PyPI | Not reported | 3.1.6 | Not reported | GHSA-29VQ-49WR-VM6X | Not reported |
| Alpine | py3-werkzeug | apk | 3.24 | 3.1.6-r0 | Not reported | ALPINE-CVE-2026-27199 | Not reported |
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [python3-werkzeug]Not affected
Source package: [python-werkzeug]
Details (2)
2.2.2-3+deb12u1· all · bookwormNot affected
nvd · python-werkzeug · debian · bookworm
2.2.2-3+deb12u1· all · bookwormNot affected
nvd · python-werkzeug · debian · bookworm
- [python-werkzeug-doc]Not affected
Source package: [python-werkzeug]
Details (2)
2.2.2-3+deb12u1· all · bookwormNot affected
nvd · python-werkzeug · debian · bookworm
2.2.2-3+deb12u1· all · bookwormNot affected
nvd · python-werkzeug · debian · bookworm
Observed:
References
- [https://nvd.nist.gov/vuln/detail/CVE-2026-27199]
- [https://osv.dev/vulnerability/ALPINE-CVE-2026-27199]
- [https://osv.dev/vulnerability/GHSA-29vq-49wr-vm6x]
- [https://security-tracker.debian.org/tracker/CVE-2026-27199]
- [https://wid.cert-bund.de/.well-known/csaf/white/2026/wid-sec-w-2026-2933.json]
[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [GitHub Advisory Database] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database]