Symlink Attack Affecting cpython package, versions [0,]
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-CONAN-CPYTHON-20341495
- published1 Oct 2026
- disclosed29 Sept 2026
- creditBitshift
Introduced: 29 Sep 2026
NewCVE-2026-12345 (opens in a new tab)How to fix?
A fix was pushed into the master branch but not yet published.
Overview
Affected versions of this package are vulnerable to Symlink Attack due to a race condition in the onexc handler of TemporaryDirectory._rmtree in Lib/tempfile.py, which responds to a PermissionError or IsADirectoryError by calling _resetperms() and os.unlink() on the absolute path, resolving that path again rather than operating relative to the directory descriptor rmtree already holds. An attacker can delete files outside the temporary directory, or reset their permissions and file flags, with the privileges of the process doing the cleanup, by replacing a directory in the tree with a symbolic link in the window between the failed operation and the retry. This requires local write access to the tree while cleanup is running and a cleanup operation that hits a permissions error to reach the handler at all, and deletion outside the tree is confined to platforms where shutil.rmtree.avoids_symlink_attacks is false, though the flag reset reaches outside the tree on every platform.