Quick answers
- Is CVE-2026-66304 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-66304 being exploited in the wild.
- How severe is CVE-2026-66304?
- High severity, with a CVSS score of 7.5, published 8 September 2026.
- Which products and versions are affected?
- Microsoft Skype for Business.
- Is there a fix for CVE-2026-66304?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-66304 attacked?
- It is attacked over the network, in a hosted service.
- Am I affected by CVE-2026-66304?
- Check whether you run Microsoft Skype for Business. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
A server-side request forgery (SSRF) vulnerability exists in Skype for Business, allowing an attacker to make arbitrary HTTP requests from the affected server. The vulnerability is network-accessible and does not require authentication, enabling an unauthorized attacker to disclose information by forcing the server to request internal or restricted resources. An attacker can leverage this to access backend services, internal APIs, or sensitive data that would normally be restricted from external access. This flaw permits information disclosure over the network without user interaction.
Affected products
- Microsoft Skype for Business
Timeline
- 2026-09-08: disclosed