CVE-2025-4517

Allows arbitrary filesystem writes outside the extraction directory during extraction with filter="data".


You are affected by this vulnerability if using the tarfile module to extract untrusted tar archives using TarFile.extractall() or TarFile.extract() using the filter= parameter with a value of "data" or "tar". See the tarfile extraction filters documentation https://docs.python.org/3/library/tarfile.html#tarfile-extraction-filter  for more information.

Note that for Python 3.14 or later the default value of filter= changed from "no filtering" to `"data", so if you are relying on this new default behavior then your usage is also affected.

Note that none of these vulnerabilities significantly affect the installation of source distributions which are tar archives as source distributions already allow arbitrary code execution during the build process. However when evaluating source distributions it's important to avoid installing source distributions with suspicious links.

• https://gist.github.com/sethmlarson/52398e33eff261329a0180ac1d54f42f

  cna@python.org
• https://github.com/python/cpython/commit/19de092debb3d7e832e5672cc2f7b788d35951da

  cna@python.org
• https://github.com/python/cpython/commit/28463dba112af719df1e8b0391c46787ad756dd9

  cna@python.org
• https://github.com/python/cpython/commit/3612d8f51741b11f36f8fb0494d79086bac9390a

  cna@python.org
• https://github.com/python/cpython/commit/4633f3f497b1ff70e4a35b6fe2c907cbe2d4cb2e

  cna@python.org
• https://github.com/python/cpython/commit/9c1110ef6652687d7c55f590f909720eddde965a

  cna@python.org
• https://github.com/python/cpython/commit/9e0ac76d96cf80b49055f6d6b9a6763fb9215c2a

  cna@python.org
• https://github.com/python/cpython/commit/aa9eb5f757ceff461e6e996f12c89e5d9b583b01

  cna@python.org
• https://github.com/python/cpython/commit/dd8f187d0746da151e0025c51680979ac5b4cfb1

  cna@python.org
• https://github.com/python/cpython/issues/135034

  cna@python.org
• https://github.com/python/cpython/pull/135037

  cna@python.org
• https://mail.python.org/archives/list/security-announce@python.org/thread/MAXIJJCUUMCL7ATZNDVEGGHUMQMUUKLG/

  cna@python.org