CVE-2026-66304: Skype for Business Information Disclosure Vulnerability

Overview

Severity

High (CVSS 7.5)

CVSS Vector

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

Category

Information Disclosure

Exploit Status

Not Exploited

Exploitation Likelihood

Less Likely

Patch Tuesday

2026-Sep

Released

2026-09-08

Description

Server-side request forgery (ssrf) in Skype for Business allows an unauthorized attacker to disclose information over a network.

FAQ

How could an attacker exploit this vulnerability? An attacker would have to make the service attempt to connect to the malicious server, leading to a Server-side request forgery.

Affected Products (3)

Microsoft Office

• Skype for Business Server 2019 CU8
• Skype for Business Server Subscription Edition CU1
• Skype for Business Server 2015 CU13

Security Updates (1)

• 5123287

Acknowledgments

Manish Kumar, Pranjal Varshney

Revision History

• 2026-09-08: Information published.