CVE intelligence

CVE-2026-120633

Vulnerability intelligence

Published Nov 4, 2026Sources checked Nov 7, 2026

N/ACVSS not listedScore unavailable

What this means

Review the available evidence

CVE-2026-120633. 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

EPSS0.1%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-120633?

CGI versions before 5.00 for Perl trust the client X-Forwarded-Host header in url, self_url, virtual_host and virtual_port.

These take the host name and port from the X-Forwarded-Host request header when present, and otherwise from Host, without validating either. The URLs from url and self_url are the default redirect location and the start_html(-base=>1) base href, and the default start_form action when REQUEST_URI is not set.

A client can poison shared caches, and URLs the application stores or sends, with redirects, links and scripts that point at a host it controls.

Source: NVD