CVE intelligence

CVE-2026-39823

Vulnerability intelligence

Published May 7, 2026Sources checked Nov 11, 2026

6.1MEDIUMCVSS out of 10

What this means

Review the available evidence

CVE-2026-39823 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.

What to do next

Remediation and response

Microsoft Security Response Center guidance

Vendor revision: Sep 17, 2026

See the Microsoft Security Update Guide for the update that applies to your product.

CISA KEVNot listedBased on the latest collected catalog

EPSS0.3%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-39823?

CVE-2026-27142 fixed a vulnerability in which URLs were not correctly escaped inside of a <meta> tag's <content> attribute. If the URL content were to insert ASCII whitespaces around the '=' rune inside of the <content> attribute, the escaper would fail to similarly escape it, leading to XSS.

Source: NVD