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

Published Nov 3, 2026 CVSS 3.1 · 6.1 Medium EPSS < 1% KEV · Not listed
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, /&#47;evil.example/ becomes //evil.example/ and sends the user to another host.

Remediation

Vendor Solution

Upgrade to CGI 5.00 or later.


Vendor Workaround

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

Tracking

Sign in to view the affected projects.

Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

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

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, /&#47;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

Subscriptions

No data.

Weaknesses

Sources

Status
PUBLISHED
Assigner
CPANSec
Published
Updated
Nov 9, 2026, 6:50 PM
Reserved
Nov 2, 2026, 5:40 PM
Status
Deferred
Published
Nov 4, 2026, 12:17 AM
Modified
Nov 9, 2026, 7:16 PM
Severity
Moderate
Public date
Nov 3, 2026, 11:40 PM