Denial of Service Vulnerability in Skype for Business by Microsoft
CVE-2026-66307

7.5HIGH

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-2026-66307?

An integer underflow vulnerability in Skype for Business allows an unauthorized attacker to exploit the system and induce a denial of service condition over the network. This could lead to service interruptions for users, potentially affecting both communication and productivity. Organizations using affected versions should apply the recommended patches to mitigate this risk.

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:
7.5
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.