CVE-2026-66305: Skype for Business Spoofing Vulnerability
Published Sep 8, 2026
·Updated
Skype for Business Spoofing Vulnerability
Other sources
Use of client-side authentication in Skype for Business allows an authorized attacker to perform spoofing over a network.
— Microsoft
Affected Software
9 affected componentsFixes available
Microsoft Skype for Business Server 2015 CU13<6.0.9319.885
6.0.9319.885
Microsoft Skype for Business Server 2019 CU8<7.0.2046.569
7.0.2046.569
Microsoft Skype for Business Server Subscription Edition CU1<7.0.2046.879
7.0.2046.879
Microsoft Skype for Business Server=2015-cumulative_update_13
Microsoft Skype for Business Server=2015-cumulative_update_13_hotfix_2
Microsoft Skype for Business Server=2019-cumulative_update_8
Microsoft Skype for Business Server=2019-cumulative_update_8_hotfix1
Microsoft Skype for Business Server=2019-cumulative_update_8_hotfix2
Microsoft Skype For Business Server Subscription Edition=7.0.2046.849
Remediation
Event History
Sep 8, 2026
CVE Published
via Microsoft·02:00 PM
Data Sourced
via Microsoft·02:00 PM
DescriptionSeverityWeaknessAffected Software
CVE Published
via MITRE·06:32 PM
Data Sourced
via MITRE·06:32 PM
DescriptionSeverity
Data Sourced
via NVD·07:18 PM
RemedyDescriptionSeverityWeaknessAffected Software
Frequently Asked Questions
1
Which deployments are identified as affected?
The affected software listed is Microsoft Skype for Business Server 2015 CU13, Skype for Business Server 2019 CU8, and Skype for Business Server Subscription Edition CU1.
2
What access does an attacker need to exploit this issue?
The attacker must be authorized and able to act over a network. The provided information does not indicate that user interaction is required.