medium6.3
CVE-2025-66221
Werkzeug safe_join() allows Windows special device names
Impact
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.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| pip | werkzeug | < 3.1.4 | 3.1.4 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Palletsprojects | Werkzeug | before 3.1.4 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/pallets/werkzeug/commit/4b833376a45c323a189cd11d2362bcffdb1c0c13
- https://github.com/pallets/werkzeug/releases/tag/3.1.4
- https://github.com/pallets/werkzeug/security/advisories/GHSA-hgf8-39gv-g3f2
- https://github.com/advisories/GHSA-hgf8-39gv-g3f2
- https://nvd.nist.gov/vuln/detail/CVE-2025-66221