CVE-2026-120638

CGI versions before 5.00 for Perl allow open redirects via HTML entity decoding of the URL after application validation in redirect

publishedCWE-180CWE-601

CGI versions before 5.00 for Perl allow open redirects via HTML entity decoding of the URL after application validation in redirect. redirect decodes HTML entities in its URL before writing the Location header, so a URL the application has already validated can change meaning. For example, //evil.example/ becomes //evil.example/ and sends the user to another host.

Technical severityUnscoredNo score in collected sources

Published2026-11-03Source updated 2026-11-03

Collected2026-11-041 attributed source

Fixes and workarounds

Fix

Upgrade to CGI 5.00 or later.

Source: CNA: CPANSec

Workaround

For deployments that cannot upgrade, reject redirect URLs that HTML entity decoding would change.

Source: CNA: CPANSec

Fix

The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.

Source: CNA: CPANSec

Affected products and versions

Affected products, source version ranges and reporting authorities
Product	Versions	Authority
`CGI` cpan	≥ 0; < 5.00 (affected, custom) Other versions: unaffected	CNA: CPANSec

Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.

CVSS assessments

No CVSS assessment reported. An unscored record is not a low-severity determination.

Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

References

https://metacpan.org/release/LEEJO/CGI-4.72/source/lib/CGI.pmCNA: CPANSec · technical-description
https://metacpan.org/release/LEEJO/CGI-5.00/changesCNA: CPANSec · release-notes
https://github.com/leejo/CGI.pm/commit/7733c2753f4f240012097507cda2b6e87ae46db4.patchCNA: CPANSec · patch

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