CVE-2025-4517
Arbitrary writes via tarfile realpath overflow
- Published
- Updated
- Reserved
- Assigned by
- PSF
Description
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.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| PSFCNA (assigner) | 3.1 | Critical9.4 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L |
| NVDNVD · Deferred | 3.1 | Critical9.4 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L |
- EPSS (exploitation in 30 days)
- 1.5% · top 26% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 9.4.
Weakness
Affected products
Python Software Foundation · CPython
- affected < 3.9.23
- affected 3.10.0 – < 3.10.18
- affected 3.11.0 – < 3.11.13
- affected 3.12.0 – < 3.12.11
- affected 3.13.0 – < 3.13.4
- affected 3.14.0a1 – < 3.14.0b3
References (12)
- https://github.com/python/cpython/issues/135034 (opens in a new tab)issue-tracking
- https://github.com/python/cpython/pull/135037 (opens in a new tab)patch
- https://mail.python.org/archives/list/[email protected]/thread/MAXIJJCUUMCL7ATZNDVEGGHUMQMUUKLG/ (opens in a new tab)vendor-advisory
- https://github.com/python/cpython/commit/3612d8f51741b11f36f8fb0494d79086bac9390a (opens in a new tab)patch
- https://github.com/python/cpython/commit/9e0ac76d96cf80b49055f6d6b9a6763fb9215c2a (opens in a new tab)patch
- https://gist.github.com/sethmlarson/52398e33eff261329a0180ac1d54f42f (opens in a new tab)mitigation
- https://github.com/python/cpython/commit/19de092debb3d7e832e5672cc2f7b788d35951da (opens in a new tab)patch
- https://github.com/python/cpython/commit/aa9eb5f757ceff461e6e996f12c89e5d9b583b01 (opens in a new tab)patch
- https://github.com/python/cpython/commit/28463dba112af719df1e8b0391c46787ad756dd9 (opens in a new tab)patch
- https://github.com/python/cpython/commit/4633f3f497b1ff70e4a35b6fe2c907cbe2d4cb2e (opens in a new tab)patch
- https://github.com/python/cpython/commit/9c1110ef6652687d7c55f590f909720eddde965a (opens in a new tab)patch
- https://github.com/python/cpython/commit/dd8f187d0746da151e0025c51680979ac5b4cfb1 (opens in a new tab)patch
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2025-4517)Record last updated .