Sep 2026: Skype for Business and Lync Denial of Service Vulnerability
CVE-2026-66303 Published on September 8, 2026

Skype for Business and Lync Denial of Service Vulnerability
Null pointer dereference in Skype for Business allows an authorized attacker to deny service over a network.

Vendor Advisory NVD

Weakness Type

NULL Pointer Dereference

A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. NULL pointer dereference issues can occur through a number of flaws, including race conditions, and simple programming omissions.


Products Associated with CVE-2026-66303

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Affected Versions

Microsoft Skype for Business Server 2015 CU13: Microsoft Skype for Business Server 2019 CU8: Microsoft Skype for Business Server Subscription Edition CU1: