Link following in Python - CVE-2025-4138
Published: June 26, 2025 / Updated: April 1, 2026
Vulnerability identifier: #VU111968
CSH Severity: High
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P/U:Amber
CVE-ID: CVE-2025-4138
CWE-ID: CWE-59
Exploitation vector: Remote access
Exploit availability:
Public exploit is available
Vendor: Python.org
Affected software:
Python
Python
Detailed vulnerability description
The vulnerability allows a remote attacker to compromise the affected system.
The vulnerability exists due to an insecure link following issue when extracting data from an archive in the tarfile module. A remote attacker can pass a specially crafted archive to the application and overwrite arbitrary files outside the destination directory during extraction with filter="data"..
How to mitigate CVE-2025-4138
Install updates from vendor's website.
Sources
- https://gist.github.com/sethmlarson/52398e33eff261329a0180ac1d54f42f
- https://github.com/python/cpython/commit/19de092debb3d7e832e5672cc2f7b788d35951da
- https://github.com/python/cpython/commit/28463dba112af719df1e8b0391c46787ad756dd9
- https://github.com/python/cpython/commit/3612d8f51741b11f36f8fb0494d79086bac9390a
- https://github.com/python/cpython/commit/4633f3f497b1ff70e4a35b6fe2c907cbe2d4cb2e
- https://github.com/python/cpython/commit/9c1110ef6652687d7c55f590f909720eddde965a
- https://github.com/python/cpython/commit/9e0ac76d96cf80b49055f6d6b9a6763fb9215c2a
- https://github.com/python/cpython/commit/aa9eb5f757ceff461e6e996f12c89e5d9b583b01
- https://github.com/python/cpython/commit/dd8f187d0746da151e0025c51680979ac5b4cfb1
- https://github.com/python/cpython/issues/135034
- https://github.com/python/cpython/pull/135037
- https://mail.python.org/archives/list/security-announce@python.org/thread/MAXIJJCUUMCL7ATZNDVEGGHUMQMUUKLG/