CVE-2026-66307 HIGH

CVE-2026-66307: Skype for Business and Lync Denial of Service Vulnerability

Vendor Microsoft
Product Skype for Business Server 2015 CU13
Weakness CWE-191
Published September 8, 2026
Last update September 29, 2026
View on NVD All CVEs

CVSS base score

7.5/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality None
Integrity None

CVSS vector

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

What the vulnerability does

01Description

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

Key dates

02Disclosure timeline

September 8, 2026 CVE published
September 29, 2026 Record updated