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.
Advisories

No advisories yet.

Fixes

Solution

Upgrade to CGI 5.00 or later.


Workaround

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

History

Wed, 04 Nov 2026 12:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 6.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N'}

threat_severity

Moderate


Wed, 04 Nov 2026 00:00:00 +0000

Type Values Removed Values Added
Description 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.
Title CGI versions before 5.00 for Perl allow open redirects via HTML entity decoding of the URL after application validation in redirect
Weaknesses CWE-180
CWE-601
References

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: CPANSec

Published:

Updated: 2026-11-03T23:40:27.142Z

Reserved: 2026-11-02T17:40:51.554Z

Link: CVE-2026-120638

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Deferred

Published: 2026-11-04T00:17:25.137

Modified: 2026-11-04T18:42:35.810

Link: CVE-2026-120638

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-11-03T23:40:27Z

Links: CVE-2026-120638 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-11-04T13:45:14Z

Weaknesses