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BIT-setuptools-2026-59890 — setuptools: MANIFEST.in exclusion bypass in sdist via Unicode normalization collision (NFC/NFD) on macOS APFS/HFS+

Affected: Bitnami: setuptools

setuptools is a package that allows users to download, build, install, upgrade, and uninstall Python packages. Prior to 83.0.0, FileList applied MANIFEST.in exclude, global-exclude, recursive-exclude, and prune directives by matching compiled glob patterns against on-disk file names without Unicode normalization, so on macOS APFS or HFS+ an NFD file name could bypass an NFC exclusion rule and be packed into a source distribution. This issue is fixed in version 83.0.0.

CVE-2026-59890 — setuptools: MANIFEST.in exclusion bypass in sdist via Unicode normalization collision (NFC/NFD) on macOS APFS/HFS+

Affected: pypa setuptools

GHSA-h35f-9h28-mq5c — setuptools: MANIFEST.in exclusion bypass in sdist via Unicode normalization collision (NFC/NFD) on macOS APFS/HFS+

Affected: PyPI: setuptools

## Summary

When building a source distribution (`python -m build --sdist` / `setup.py sdist`), setuptools' `FileList` applies `MANIFEST.in` directives (`exclude`, `global-exclude`, `recursive-exclude`, `prune`) by matching a compiled glob against on-disk file names **byte-for-byte, with no Unicode normalization**. On normalization-preserving filesystems (notably macOS APFS and HFS+), a file written in NFD and a `MANIFEST.in` rule written in NFC refer to the same file but are byte-distinct, so the exclusion silently fails to match. A file the maintainer intended to exclude is then packed into the `.tar.gz` and, if published, uploaded to the public, immutable PyPI index.

## Details

File names in `FileList.files` come from `os.walk` (`setuptools/_distutils/filelist.py`, `_find_all_simple`), so on APFS a file written NFD is offered to the matcher in NFD, while the `MANIFEST.in` pattern carries the author's editor form (typically NFC). The matching path performs no canonicalization:

```python # setuptools/command/egg_info.py (FileList.global_exclude) def global_exclude(self, pattern): match = translate_pattern(os.path.join('**', pattern)) # fnmatch.translate -> regex, no NFC/NFD return self._remove_files(match.match) # byte-level regex over raw os.walk names ```

A rule written NFC (`café` = `63 61 66 c3 a9`) does not match an on-disk name written NFD (`café` = `63 61 66 65 cc 81`), even though the filesystem treats the two as one file.

A `unicod…

PYSEC-2026-3447

Affected: PyPI: setuptools