Quick answers
- Is CVE-2026-66306 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-66306 being exploited in the wild.
- How severe is CVE-2026-66306?
- Medium severity, with a CVSS score of 6.5, published 8 September 2026.
- Which products and versions are affected?
- Microsoft Skype for Business <UNKNOWN>.
- Is there a fix for CVE-2026-66306?
- 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-2026-66306 attacked?
- It is attacked over the network.
- Am I affected by CVE-2026-66306?
- Check whether you run Microsoft Skype for Business at an affected version. 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
Skype for Business generates error messages that inadvertently disclose sensitive information accessible to unauthenticated network attackers. The vulnerability is an information disclosure flaw stemming from improper error message handling, where detailed error responses leak confidential data such as internal configuration or user information. No authentication is required to trigger the vulnerable error condition—an attacker can send specially crafted network requests to elicit sensitive information in the error response. The attack is purely informational and does not enable direct compromise of accounts or systems, but facilitates reconnaissance for further attacks. Patch availability and specific affected versions are not detailed in the advisory summary; refer to the Microsoft Security Response Center update guide for remediation timelines.
Affected products
- Microsoft Skype for Business <UNKNOWN>
Timeline
- 2026-09-08: disclosed