CVE-2026-82049
Received Received - Intake

Hard Link to Symlink Arbitrary File Modification in CPython

Publication date: 2026-09-14

Last updated on: 2026-09-14

Assigner: Python Software Foundation

Description
In CPython 3.13 and earlier, the tarfile module's data and tar extraction filters are vulnerable to crafted archives containing a hard link to a symbolic link. Such archives may cause extraction to modify the permissions or modification time of a file outside the destination directory, or expose the contents of that file within the extracted tree.

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Meta Information

Published
2026-09-14
Last Modified
2026-09-14
Generated
2026-09-14
AI Q&A
2026-09-14
EPSS Evaluated
N/A
NVD
CVE-2026-82049
EUVD
EUVD-2026-77772

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
python cpython 3.13

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-59 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.

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Executive Summary

This vulnerability in CPython's tarfile module allows attackers to create malicious tar archives with hard links to symbolic links. When extracted, these archives can modify file permissions or timestamps outside the intended directory or expose sensitive file contents within the extracted files.

Detection Guidance

Detecting this vulnerability requires checking for tarfile module usage in Python 3.13 or earlier. Inspect Python scripts or applications using tarfile for improper handling of hard links to symbolic links. No specific commands are provided in the context.

Impact Analysis

An attacker could use this to overwrite system files, change permissions on critical files, or leak sensitive data by manipulating the tar extraction process. This could lead to system compromise or unauthorized access to files.

Compliance Impact

This vulnerability could lead to unauthorized data exposure or modification, violating confidentiality and integrity requirements in GDPR and HIPAA. Organizations may face compliance violations if exploited.

Mitigation Strategies

Upgrade to a patched version of Python beyond 3.13 where the tarfile module vulnerability is fixed. Avoid using untrusted tar archives until the upgrade is complete. Review and update extraction logic to handle hard links and symbolic links safely.

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