Default mimetype known files writeable on Windows
CVE-2024-3220 is fixed in Python 3.14 on 2 platforms by Python 3.14 3.14.9 (version 3.14.9), released October 21, 2026. 11 other affected products have no fix yet. It is not reported as exploited. Patch Radar priority: Routine.
There is a defect in the CPython standard library module “mimetypes” where on Windows the default list of known file locations are writable meaning other users can create invalid files to cause MemoryError to be raised on Python runtime startup or have file extensions be interpreted as the incorrect file type. This defect is caused by the default locations of Linux and macOS platforms (such as “/etc/mime.types”) also being used on Windows, where they are user-writable locations (“C:\etc\mime.types”). To work-around this issue a user can call mimetypes.init() with an empty list (“[]”) on Windows platforms to avoid using the default list of known file locations.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Windows apps | |||
| Python 3.14 | 3.14.9 | Python 3.14 3.14.9 | Oct 21, 2026 |
| No fix yet | |||
| Python 2 (Windows apps) | No fix yet | no-fix | n/a |
| Python 3.10 (Windows apps) | No fix yet | no-fix | n/a |
| Python 3.11 (Windows apps) | No fix yet | no-fix | n/a |
| Python 3.12 (Windows apps) | No fix yet | no-fix | n/a |
| Python 3.13 (Windows apps) | No fix yet | no-fix | n/a |
| Python 3.5 (Windows apps) | No fix yet | no-fix | n/a |
| Python 3.6 (Windows apps) | No fix yet | no-fix | n/a |
| Python 3.7 (Windows apps) | No fix yet | no-fix | n/a |
| Python 3.8 (Windows apps) | No fix yet | no-fix | n/a |
| Python 3.9 (Windows apps) | No fix yet | no-fix | n/a |
| Python3 (macOS) | No fix yet | no-fix | n/a |
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