CVE-2026-66307: high-severity vulnerability in Microsoft Skype for Business Server 2015 CU13
Skype for Business and Lync Denial of Service Vulnerability
Published · Updated
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.5epss 1.2%
Integer underflow (wrap or wraparound) in Skype for Business allows an unauthorized attacker to deny service over a network.
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
Affected products
Microsoft · Skype for Business Server 2015 CU13Microsoft · Skype for Business Server 2019 CU8Microsoft · Skype for Business Server Subscription Edition CU1Related CVEs — Microsoft Skype for Business Server 2015 CU13
In the same product, most dangerous first.
CVE-2023-41763MEDIUMSkype for Business Elevation of Privilege VulnerabilityEPSS 90.3%KEVCVE-2023-36780HIGHSkype for Business Remote Code Execution VulnerabilityEPSS 2.7%CVE-2023-36786HIGHSkype for Business Remote Code Execution VulnerabilityEPSS 2.6%CVE-2023-36789HIGHSkype for Business Remote Code Execution VulnerabilityEPSS 2.5%CVE-2026-70297HIGHSkype for Business Remote Code Execution VulnerabilityEPSS 1.2%CVE-2026-83746HIGHSkype for Business Elevation of Privilege VulnerabilityEPSS 1.1%