pypa/setuptools vulnerable to Regular Expression Denial of Service (ReDoS)

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

8.7 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:L/SI:L/SA:N · score source

EPSS

• CVE-2022-40897: 2.63% estimated exploitation activity in the next 30 days; percentile 85.56 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Python Packaging Authority (PyPA)'s setuptools is a library designed to facilitate packaging Python projects. Setuptools version 65.5.0 and earlier could allow remote attackers to cause a denial of service by fetching malicious HTML from a PyPI package or custom PackageIndex page due to a vulnerable Regular Expression in packageindex. This has been patched in version 65.5.1.

Published by the source

23 Dec 2022, 00:30 UTC

Last modified by the source

7 Aug 2026, 08:12 UTC

Source last checked

26 Oct 2026, 13:35 UTC

1. Revision 3 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-r9hx-vwmv-q579

2. Revision 2 · amended · 25 Oct 2026

   Reviewed OSV alias/range/CVSS4 correction; package source scopes and original publication preserved. No customer finding resolved.

3. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-r9hx-vwmv-q579

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# Patch Next advisory brief: CVE-2022-40897

Advisory: pypa/setuptools vulnerable to Regular Expression Denial of Service (ReDoS)
IDs: CVE-2022-40897, GHSA-r9hx-vwmv-q579
Record: https://patchnext.com/advisories/cve-2022-40897 (revision 3, source checked 26 Oct 2026, 13:35 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: setuptools 65.5.1. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI setuptools: affected < 65.5.1; fixed in 65.5.1

## Suggested inspection (read-only)
- `python -m pip show setuptools`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on setuptools.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-r9hx-vwmv-q579 (OSV record GHSA-r9hx-vwmv-q579 lists affected ranges: PyPI setuptools >=0 <65.5.1 (fixed))
- Verified: https://github.com/advisories/GHSA-r9hx-vwmv-q579 (GitHub-reviewed advisory GHSA-r9hx-vwmv-q579 lists affected ranges: PyPI setuptools >=0 <65.5.1)

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