sdist · setuptools: MANIFEST.in exclusion bypass
Affects yamlfixSource GCVE Database
Not known to be exploited · CVSS 6.1 Medium : upgrade to 1.19.1_2 when convenient.
Data as of 26 Oct 2026, 19:32 UTC
- Patch
- Available – fixed in 1.19.1_2
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:NExploitation evidence
Disclosed: evidence found.
CVE published 8 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade yamlfix to 1.19.1_2.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Homebrewyamlfixpkg:brew/yamlfixOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A patch is available in setuptools version 1.19.1_2 that normalizes both the on-disk filenames and MANIFEST.in patterns to a canonical Unicode form before matching, preventing exclusion bypass. Users should upgrade to this fixed version or later. Until patched, maintainers should be aware that MANIFEST.in exclusions are normalization-insensitive on macOS and consider erring on the side of excluding more files. No other immediate actions are required.
Description
A Unicode normalization mismatch in setuptools' handling of MANIFEST.in exclusions can cause files intended to be excluded from source distributions to be included instead. This occurs on macOS APFS/HFS+ filesystems where filenames are stored in NFD form but MANIFEST.in patterns are typically in NFC form, leading to silent exclusion bypasses. This can result in unintended disclosure of sensitive files when publishing to PyPI.
References
- github.com/pypa/setuptools/security/advisories/GHSA-h35f-9h28-mq5c (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-59890 (opens in a new tab)
- github.com/pypa/setuptools/commit/dd9f436a36486b4cb8a4c70a2321548b0be09b8f (opens in a new tab)
- github.com/pypa/advisory-database/tree/main/vulns/setuptools/PYSEC-2026-3447.yaml (opens in a new tab)
- github.com/pypa/setuptools (opens in a new tab)
- github.com/pypa/setuptools/releases/tag/v83.0.0 (opens in a new tab)