Tarfile.extract filter bug in CPython <3.16 uid/gid bypass
CVE-2026-4360 Published on June 30, 2026
Tarfile.extract() doesn't fully respect filter parameter
In the Tarfile.extract() function, the filter parameter is not passed properly when extracting hardlinks. An affected system that extracts content from untrusted tar files could end up writing files with an unexpected uid/gid despite the user passing filter='data' to the extract() function.
Vulnerability Analysis
CVE-2026-4360 is exploitable with network access. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity and availability.
Weakness Type
Improper Preservation of Permissions
The software does not preserve permissions or incorrectly preserves permissions when copying, restoring, or sharing objects, which can cause them to have less restrictive permissions than intended.
Products Associated with CVE-2026-4360
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Affected Versions
Python Software Foundation CPython:- Before 3.13.15 is affected.
- Version 3.14.0 and below 3.14.7 is affected.
- Version 3.15.0a1 and below 3.15.0b4 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.