Microsoft Security Response Center guidance
Vendor revision: Sep 17, 2026See the Microsoft Security Update Guide for the update that applies to your product.
Vulnerability intelligence
CVE-2026-56858 and is rated Medium severity with a CVSS score of 6.1. It is not in the current CISA KEV record we collected. That does not prove exploitation has not occurred.
See the Microsoft Security Update Guide for the update that applies to your product.
Previously, pathological inputs could close an unescaped '/' early, allowing for attack-controlled data to inject arbitrary content, potentially leading to XSS.
Source: NVD