CVE-2026-12345

Description

The cleanup of tempfile.TemporaryDirectory is vulnerable to a race condition. An attacker who can modify the tree during cleanup can replace a directory with a symbolic link, causing files outside of the temporary directory to be deleted or have their permissions and file flags reset, with the privileges of the process performing the cleanup. Note that platforms where shutil.rmtree.avoids_symlink_attacks is false, remain affected, and file flags may still be reset outside of the tree on all platforms.

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Weakness Type (CWE)

CWE-59 CWE-59

References

Other References

https://github.com/python/cpython/commit/5c20517a4fc56683efe63a7751020db9573f538d https://github.com/python/cpython/issues/157579 https://github.com/python/cpython/pull/157580 http://www.openwall.com/lists/oss-security/2026/09/29/40

Frequently Asked Questions

What is CVE-2026-12345? +

The cleanup of tempfile.TemporaryDirectory is vulnerable to a race condition. An attacker who can modify the tree during cleanup can replace a directory with a symbolic link, causing files outside of the temporary directory to be deleted or have their permissions and file flags reset, with the privileges of the process performing the cleanup. Note that platforms where shutil.rmtree.avoids_symlink_attacks is false, remain affected, and file flags may still be reset outside of the tree on all platforms.

How do I check if I'm vulnerable to CVE-2026-12345? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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