# CVE-2026-59890: pypa setuptools Unicode normalization bypass in MANIFEST.in exclusions

Source: https://junglewise.ai/threats/cve-2026-59890-pypa-setuptools-unicode-normalization-bypass-in-manifest-in  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-08. Updated: 2026-07-21  
License: CC BY 4.0 with a link back

CVE-2026-59890 · Severity: medium · CVSS 6.1 · Published 2026-07-08

Setuptools is a widely used tool for packaging Python software. A vulnerability in its packaging process on macOS systems could cause sensitive files, such as private keys or local configuration files, to be accidentally included in public software releases even if the developer explicitly tried to exclude them. This occurs because the tool fails to recognize certain characters in filenames that look identical but are stored differently on disk, potentially leading to the irreversible exposure of private data on public repositories like PyPI.

Technologies: [setuptools (PyPI)](https://junglewise.ai/threats/technologies/pypi-setuptools). Vendors: [PyPI](https://junglewise.ai/threats/vendors/pypi).

## Quick answers

**Is CVE-2026-59890 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-59890 being exploited in the wild.

**How severe is CVE-2026-59890?** Medium severity, with a CVSS score of 6.1, published 8 July 2026.

**Which products and versions are affected?** setuptools (PyPI) ECOSYSTEM:introduced=0,fixed=83.0.0.

**Is there a fix for CVE-2026-59890?** Yes. setuptools (PyPI): upgrade to 83.0.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-59890 attacked?** It is attacked with local access, in a software library.

**Am I affected by CVE-2026-59890?** Check whether you run setuptools (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- setuptools (PyPI): upgrade to 83.0.0 or later

  ```sh
  pip install "setuptools>=83.0.0"
  ```


## Technical details

A vulnerability in setuptools' FileList component allows for the bypass of MANIFEST.in exclusion directives (e.g., exclude, global-exclude) when building source distributions (sdist) on macOS systems using APFS or HFS+ filesystems. The root cause is a byte-for-byte comparison between MANIFEST.in patterns (typically in NFC) and on-disk filenames (often in NFD) without performing Unicode normalization. An attacker or environmental condition can result in sensitive files being included in the final .tar.gz archive despite matching exclusion rules. This issue is specific to non-ASCII filenames on normalization-preserving filesystems. The vulnerability is addressed in version 83.0.0 by normalizing both paths and patterns to a canonical form before matching.

## Affected products

- pypa setuptools < 83.0.0

## Identifiers

- CVE-2026-59890
- GHSA-h35f-9h28-mq5c
- PYSEC-2026-3447

## Timeline

- 2026-07-04: disclosed: Initial disclosure date reported by researcher
- 2026-07-04: patched: Version 83.0.0 released
- 2026-07-21: advisory: GitHub Advisory published

## References

- [https://api.github.com/users/tomasilluminati](https://api.github.com/users/tomasilluminati)
- [https://github.com/tomasilluminati](https://github.com/tomasilluminati)
- [https://api.github.com/users/tomasilluminati/gists%7B/gist_id%7D](https://api.github.com/users/tomasilluminati/gists%7B/gist_id%7D)
- [https://api.github.com/users/tomasilluminati/repos](https://api.github.com/users/tomasilluminati/repos)
- [https://avatars.githubusercontent.com/u/147225560?v=4](https://avatars.githubusercontent.com/u/147225560?v=4)
- [https://api.github.com/users/tomasilluminati/events%7B/privacy%7D](https://api.github.com/users/tomasilluminati/events%7B/privacy%7D)

## Related threats

- [setuptools path escape via namespace_packages.txt on Windows](https://junglewise.ai/threats/setuptools-windows-path-escape-via-namespace-packages-txt-during-legacy-93ae767b)
- [PYSEC-2026-1918 - setuptools vulnerable to Command Injection via package URL](https://junglewise.ai/threats/cve-2024-6345-setuptools-vulnerable-to-command-injection-via-package-url)
- [setuptools has a path traversal vulnerability in PackageIndex.download that leads to Arbitrary File Write](https://junglewise.ai/threats/cve-2025-47273-setuptools-has-a-path-traversal-vulnerability-in-packageindex)
- [pypa/setuptools vulnerable to Regular Expression Denial of Service (ReDoS)](https://junglewise.ai/threats/cve-2022-40897-pypa-setuptools-vulnerable-to-regular-expression-denial-of)
- [Setuptools man-in-the-middle attack in package installation](https://junglewise.ai/threats/cve-2013-1633-setuptools-man-in-the-middle-attack-in-package-installation)