Microsoft Security Response CenterCVE-2026-66307

Skype for Business and Lync Denial of Service Vulnerability

HighVendor CVSS 7.5 / 10 1 CVE Published Sep 8, 2026 at 7:00 AM UTC

Summary

Integer underflow (wrap or wraparound) in Skype for Business allows an unauthorized attacker to deny service over a network.

Install KB5123301. Install KB5123287. Install KB5123300.

Sep 8, 2026 at 7:00 AM UTC
Published by Microsoft Security Response Center
The publication date reported by the vendor.
Sep 8, 2026 at 7:15 PM UTC
Added to SecurityAlert
We collected the advisory from the official source.
Oct 28, 2026 at 3:45 AM UTC
Confirmed at the source
Our collector saw this advisory during a later source check.

Details collected from Microsoft Security Response Center.

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