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Fencer Intel
high 7.8

CVE-2020-16156 json

CPAN 2.28 allows Signature Verification Bypass.

published 4y ago modified 4mo ago also EUVD-2020-8122

cvss
7.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.9%
EPSS 0.9% chance of exploitation in 30 days, percentile 58%
public exploits
0
none known

Summary

CPAN 2.28 allows Signature Verification Bypass.

Patch / fix

  • perl Debian 14, Debian 13, Debian 12 5.36.0-4

debian advisories DEBIAN-CVE-2020-16156

  • perl Ubuntu 18.04 LTS 5.26.1-6ubuntu0.6
  • perl Ubuntu 20.04 LTS 5.30.0-9ubuntu0.3
  • perl Ubuntu 22.04 LTS 5.34.0-3ubuntu1.1
  • perl Ubuntu Pro 14.04 LTS 5.18.2-2ubuntu1.7+esm4
  • perl Ubuntu Pro 16.04 LTS 5.22.1-9ubuntu0.9+esm1

ubuntu advisories UBUNTU-CVE-2020-16156

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • perl-CPAN RHEL 8 2.18-402.el8_10

red hat advisories RHSA-2025:8432

  • perl-CPAN AlmaLinux 8 2.18-402.el8_10

almalinux advisories ALSA-2025:8432

  • perl-CPAN Rocky Linux 8 2.18-402.el8_10

rocky linux advisories RLSA-2025:8432

Is CVE-2020-16156 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-16156 updated cvss 7.8

perl-CPAN: Bypass of verification of signatures in CHECKSUMS files

  • Red Hat Enterprise Linux 6 perl, perl-CGI, perl-core, perl-CPAN, perl-libs, perl-parent, +39 more Red Hat Enterprise Linux 7 perl, perl-core, perl-CPAN, perl-libs, perl-tests, perl-macros, +11 more
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux 8 perl-CPAN Red Hat Software Collections rh-perl530-perl-CPAN
    affected: workaround, no fix planned “Will not fix”
  • Red Hat Enterprise Linux AppStream (v. 8) perl-CPAN 2.18-402.el8_10
    fixed: vendor fix RHSA-2025:8432
  • Red Hat Enterprise Linux 8 perl, perl-IO, perl-libs, perl-open, perl-Test, perl-Errno, +19 more Red Hat Enterprise Linux 9 perl, perl-B, perl-if, perl-IO, perl-ph, perl-lib, +93 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.86% chance of exploitation in the next 30 days, higher than 58% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • blog.hackeriet.no https://blog.hackeriet.no/cpan-signature-verification-vulnerabilities/ referenced PoC, tagged "exploit" by a source, unverified
  • blogs.perl.org http://blogs.perl.org/users/neilb/2021/11/addressing-cpan-vulnerabilities-related-to-checksums.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
NVD 2.0 6.8 AV:N/AC:M/Au:N/C:P/I:P/A:P

Classification

Weakness
  • CWE-347 Improper Verification of Cryptographic Signature

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.