CVE-2026-120638. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.
What to do next
Remediation and response
Microsoft Security Response Center guidance
Vendor revision: Nov 7, 2026
Release Notes
CISA KEVNot listedBased on the latest collected catalog
EPSS0.2%Estimated 30-day exploitation probability
Ransomware useNot markedCISA KEV ransomware field
Threat actors0Source-linked actor relationships
Overview
What is 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.
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.