Spoofing Vulnerability in Skype for Business by Microsoft
CVE-2026-66305

7.1HIGH

Key Information:

Vendor

Microsoft
Status
Skype For Business Server 2015 Cu13
Skype For Business Server 2019 Cu8
Skype For Business Server Subscription Edition Cu1
Vendor
CVE Published:
8 September 2026

What is CVE-2026-66305?

A vulnerability in Skype for Business enables an unauthorized attacker to exploit client-side authentication, allowing the potential for network spoofing attacks. This can lead to unauthorized access to data and communication, posing a significant risk for users. Affected products should be updated promptly to mitigate this threat.

Affected Version(s)

Skype for Business Server 2015 CU13 x64-based Systems 9319.0 < 6.0.9319.885

Skype for Business Server 2019 CU8 x64-based Systems 2046.0 < 7.0.2046.569

Skype for Business Server Subscription Edition CU1 x64-based Systems 2046.0 < 7.0.2046.879

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE...
vendor-advisorypatch

CVSS V3.1

Score:
7.1
Severity:
HIGH
Confidentiality:
Low
Integrity:
High
Availability:
Low
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.