Quick answers
- Is CVE-2026-4360 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-4360 being exploited in the wild.
- How severe is CVE-2026-4360?
- Informational severity, with a CVSS score of 2, published 30 June 2026.
- Which products and versions are affected?
- Python Software Foundation CPython < 3.16.0.
- Is there a fix for CVE-2026-4360?
- A patch was published on 2026-06-29: Fix merged into CPython main branch Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-4360 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-4360?
- Check whether you run Python Software Foundation CPython at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
A vulnerability exists in the `Tarfile.extract()` function of Python's `tarfile` module where the `filter` parameter is not correctly passed when extracting hardlinks whose targets are missing. In such cases, the file is extracted from the archive rather than linked, but the security filter (such as `filter='data'`) is bypassed. An attacker providing a malicious tar archive can cause files to be written with unexpected UID/GID values, violating the security guarantees of the extraction filter. This is classified as a failure to properly preserve permissions (CWE-281). The issue is addressed in CPython versions 3.10 through 3.15 via backported security fixes and is fully resolved in version 3.16.0.
Affected products
- Python Software Foundation CPython < 3.16.0
Timeline
- 2026-06-23: disclosed: Issue reported on CPython GitHub repository
- 2026-06-29: patched: Fix merged into CPython main branch
- 2026-06-30: advisory: Security announcement and CVE publication