Sep 2026: Skype for Business Information Disclosure Vulnerability
CVE-2026-66304 Published on September 8, 2026
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.
Weakness Type
What is a SSRF Vulnerability?
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination. By providing URLs to unexpected hosts or ports, attackers can make it appear that the server is sending the request, possibly bypassing access controls such as firewalls that prevent the attackers from accessing the URLs directly. The server can be used as a proxy to conduct port scanning of hosts in internal networks, use other URLs such as that can access documents on the system (using file://), or use other protocols such as gopher:// or tftp://, which may provide greater control over the contents of requests.
CVE-2026-66304 has been classified to as a SSRF vulnerability or weakness.
Products Associated with CVE-2026-66304
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Affected Versions
Microsoft Skype for Business Server 2015 CU13:- Version 9319.0 and below 6.0.9319.885 is affected.
- Version 2046.0 and below 7.0.2046.569 is affected.
- Version 2046.0 and below 7.0.2046.879 is affected.