CVE intelligence

CVE-2026-120639

Vulnerability intelligence

Published Nov 4, 2026Sources checked Nov 7, 2026

N/ACVSS not listedScore unavailable

What this means

Review the available evidence

CVE-2026-120639. 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-2026-120639?

CGI versions before 5.00 for Perl allow HTTP header injection via entity decoding after the newline check in header and unchecked values in multipart_start and do_push.

With autoEscape off, header decodes HTML entities in extra header values after its newline check, so an encoded CR or LF reaches the response. multipart_start does not check header values for newlines, and do_push does not check the type it prints in each part.

An application that passes request data into these header values can be made to add headers or split the response.

Source: NVD