MSRC-CVE-2026-66304 — Skype for Business Information Disclosure Vulnerability

Summary

Impact: Information Disclosure. Microsoft rating: Important. Not known to be exploited — Exploitation Less Likely. Customer action: Required.

Details

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.

Security updates
7.0.2046.569 — https://support.microsoft.com/help/5123300
7.0.2046.879 — https://support.microsoft.com/help/5123287
6.0.9319.885 — https://support.microsoft.com/help/5123301

Vulnerabilities 1

High 7.5

CVE-2026-66304

Skype for Business Information Disclosure Vulnerability

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

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

Sep 8, 2026

Revision history

2026-09-08 #1
Information published.

References

CVE-2026-66304 Skype for Business Information Disclosure Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-66304
Microsoft Exploitability Index
https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1
Microsoft Support Lifecycle
https://support.microsoft.com/lifecycle
Common Vulnerability Scoring System
https://www.first.org/cvss