CVE-2025-66221

NameCVE-2025-66221
DescriptionWerkzeug is a comprehensive WSGI web application library. Prior to version 3.1.4, Werkzeug's safe_join function allows path segments with Windows device names. On Windows, there are special device names such as CON, AUX, etc that are implicitly present and readable in every directory. 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 patched in version 3.1.4.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
python-werkzeug (PTS)bullseye1.0.1+dfsg1-2+deb11u1fixed
bullseye (security)1.0.1+dfsg1-2+deb11u2fixed
bookworm2.2.2-3+deb12u1fixed
forky, sid, trixie3.1.3-2fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
python-werkzeugsource(unstable)(not affected)

Notes

- python-werkzeug <not-affected> (Only affects werkzeug on Windows)
https://github.com/pallets/werkzeug/security/advisories/GHSA-hgf8-39gv-g3f2
https://github.com/pallets/werkzeug/commit/4b833376a45c323a189cd11d2362bcffdb1c0c13 (3.1.4)

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