CVE-2026-66303

Null pointer dereference in Skype for Business allows an authorized attacker to deny service over a network.

Scoring

Severity

MEDIUM

CVSS base score

6.5

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C

EPSS probability

0.79%

CWE

CWE-476

Published

2026-09-08

Last modified

2026-09-10

Affected products

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

Weakness type

• CWE-476

Related vulnerabilities

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• CVE-2026-77901 — Microsoft Office Word Remote Code Execution Vulnerability
• CVE-2026-70575 — Windows Schannel Denial of Service Vulnerability
• CVE-2026-69881 — Windows Internet Key Exchange (IKE) Extension Denial of Service Vulnerability
• CVE-2026-69384 — Virtual Hard Disk (VHD) Miniport Driver Denial of Service Vulnerability
• CVE-2026-62762 — Windows Active Directory Domain Services Denial of Service Vulnerability
• CVE-2026-72949 — Windows SMB Server Network Transport Driver (srvnet.sys) Denial of Service Vulnerability
• CVE-2026-77489 — Windows Biometric Service Elevation of Privilege Vulnerability

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