CVE-2020-16155: The CPAN::Checksums package 2.12 for Perl does not uniquely define signed data.

This month

MEDIUM 6.5DOWNGRADE

CVE-2020-16155 is a medium-severity flaw (CVSS 6.5) affecting \. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The CPAN::Checksums package 2.12 for Perl does not uniquely define signed data.

Why this priority

Public exploit reference

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	1.0% (top 37%)
CISA exploited list	No
Published	2021-12-13
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: cpan\

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-12-13 18:15 UTCPublished CVE record published
2026-06-17 02:57 UTCUpdated Record last modified

cpan\ \ DOWNGRADE

Affected: checksums_project cpan\

Fixed in: no fixed release known

Safe to downgrade to: a release before checksums_project

1. Check installed version

apt-cache policy || rpm -q || --version

2. No fixed release: DOWNGRADE to a release before checksums_project (Debian / Ubuntu)

apt-cache madison sudo apt install =<VERSION_BEFORE_checksums_project> sudo apt-mark hold

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list sudo dnf downgrade -<VERSION_BEFORE_checksums_project> sudo dnf versionlock add

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2020-16155?

\: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2020-16155 being exploited?

CVE-2020-16155 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2020-16155 affect?

CVE-2020-16155 affects \. Severity is medium (CVSS 6.5). The CPAN::Checksums package 2.12 for Perl does not uniquely define signed data.

How urgent is CVE-2020-16155?

Priority 43/100. Public exploit reference

Software pages

Perl vulnerabilities

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References

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