CVE-2026-12345: python software foundation cpython Link Following

Vulnerability summary

CVE-2026-12345 is a medium (CVSS 5.9) Link Following vulnerability in python software foundation cpython. EPSS estimates a 0.18% chance of exploitation in the next 30 days, higher than 7.1% of scored vulnerabilities.

Timeline

1. 29-09-2026
   PublishedVulnerability first disclosed.
2. 10-10-2026
   Last modifiedVulnerability information updated.

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.

• CWE-59Improper Link Resolution Before File Access ('Link Following')The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.