CVE intelligence

CVE-2026-66305

Vulnerability intelligence

Published Sep 8, 2026Sources checked Oct 28, 2026

7.1HIGHCVSS out of 10

What this means

Review the available evidence

CVE-2026-66305 and is rated High severity with a CVSS score of 7.1. 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 8, 2026

Install KB5123301. Install KB5123300. Install KB5123287.

Vendor-listed releases

6.0.9319.885
7.0.2046.569
7.0.2046.879

CISA KEVNot listedBased on the latest collected catalog

EPSS0.5%Estimated 30-day exploitation probability

Ransomware useNot markedCISA KEV ransomware field

Threat actors0Source-linked actor relationships

Overview

What is CVE-2026-66305?

Use of client-side authentication in Skype for Business allows an authorized attacker to perform spoofing over a network.

Source: NVD