setuptools has a path traversal vulnerability in PackageIndex.download that leads to Arbitrary File Write
Summary
A path traversal vulnerability in PackageIndex was fixed in setuptools version 78.1.1
Details
def _download_url(self, url, tmpdir):
# Determine download filename
#
name, _fragment = egg_info_for_url(url)
if name:
while '..' in name:
name = name.replace('..', '.').replace('\\', '_')
else:
name = "__downloaded__" # default if URL has no path contents
if name.endswith('.[egg.zip](http://egg.zip/)'):
name = name[:-4] # strip the extra .zip before download
--> filename = os.path.join(tmpdir, name)os.path.join() discards the first argument tmpdir if the second begins with a slash or drive letter.
name is derived from a URL without sufficient sanitization. While there is some attempt to sanitize by replacing instances of '..' with '.', it is insufficient.
Risk Assessment
As easy_install and package_index are deprecated, the exploitation surface is reduced. However, it seems this could be exploited in a similar fashion like https://github.com/advisories/GHSA-r9hx-vwmv-q579, and as described by POC 4 in https://github.com/advisories/GHSA-cx63-2mw6-8hw5 report: via malicious URLs present on the pages of a package index.
Impact
An attacker would be allowed to write files to arbitrary locations on the filesystem with the permissions of the process running the Python code, which could escalate to RCE depending on the context.
References
https://huntr.com/bounties/d6362117-ad57-4e83-951f-b8141c6e7ca5 https://github.com/pypa/setuptools/issues/4946
Affected software
Click a technology to see all vulnerabilities affecting it.
| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | setuptools | < 78.1.1 | 78.1.1 |
References
- https://github.com/pypa/setuptools/security/advisories/GHSA-5rjg-fvgr-3xxf
- https://lists.debian.org/debian-lts-announce/2025/05/msg00035.html
- https://github.com/pypa/setuptools/issues/4946
- https://github.com/pypa/setuptools/commit/250a6d17978f9f6ac3ac887091f2d32886fbbb0b
- https://github.com/pypa/setuptools/blob/6ead555c5fb29bc57fe6105b1bffc163f56fd558/setuptools/package_index.py#L810C1-L825C88
- https://nvd.nist.gov/vuln/detail/CVE-2025-47273
- https://github.com/pypa/advisory-database/tree/main/vulns/setuptools/PYSEC-2025-49.yaml
- https://github.com/pypa/setuptools
- CVSS vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P- Weakness (CWE)
CWE-22- Platform
- Python (PyPI)
- Package
setuptools- Disclosed
- 17.05.2025
- Updated
- 11.10.2026 15:17
Sources and licenses
OSV / GitHub Advisory Database - PYSEC-2025-49 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-5rjg-fvgr-3xxf - CC BY 4.0
Vulnerability history: setuptools
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 5
- First → latest
- 08.2013 07.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 4
- Medium 1
Disclosures per year
- 2017: 0
- 2018: 0
- 2019: 0
- 2020: 0
- 2021: 0
- 2022: 1
- 2023: 0
- 2024: 1
- 2025: 1
- 2026: 1
earlier: 1
-
setuptools has a path traversal vulnerability in PackageIndex.download that leads to Arbitrary File Write this entry
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