# CVE-2026-66302: Microsoft Skype for Business arbitrary code execution via path traversal

Source: https://junglewise.ai/threats/cve-2026-66302-microsoft-skype-for-business-arbitrary-code-execution-via-path  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-08. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-66302 · Severity: critical · CVSS 9.8 · Published 2026-09-08

Skype for Business is a widely-deployed enterprise communication platform used for messaging, voice, and video conferencing across organizations. An external attacker can exploit a path traversal vulnerability to execute arbitrary code remotely without authentication, potentially compromising user endpoints, intercepting communications, or gaining footholds for lateral movement within corporate networks.

Technologies: [Microsoft Skype for Business](https://junglewise.ai/threats/technologies/skype-for-business). Vendors: [Microsoft](https://junglewise.ai/threats/vendors/microsoft).

## Quick answers

**Is CVE-2026-66302 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-66302 being exploited in the wild.

**How severe is CVE-2026-66302?** Critical severity, with a CVSS score of 9.8, published 8 September 2026.

**Which products and versions are affected?** Microsoft Skype for Business.

**Is there a fix for CVE-2026-66302?** 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-2026-66302 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-66302?** 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

The vulnerability is a path traversal / external control of file name flaw in Skype for Business that permits remote code execution. An unauthenticated attacker on the network can craft malicious input to manipulate file paths, causing the application to load and execute arbitrary code. The attack requires no user interaction or authentication. Successful exploitation grants full execution context on affected systems.

## Affected products

- Microsoft Skype for Business

## Timeline

- 2026-09-08: disclosed

## References

- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-66302](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-66302)

## Related threats

- [Microsoft Skype for Business and Lync privilege escalation](https://junglewise.ai/threats/cve-2026-85873-improper-authorization-in-skype-for-business-and-microsoft-lync)
- [Microsoft Skype for Business cryptographic signature spoofing](https://junglewise.ai/threats/cve-2026-69646-microsoft-skype-for-business-cryptographic-signature-spoofing)
- [Microsoft Skype for Business cross-site scripting in web page generation](https://junglewise.ai/threats/cve-2026-69642-microsoft-skype-for-business-cross-site-scripting-in-web-page)
- [Microsoft Skype for Business out-of-bounds read](https://junglewise.ai/threats/cve-2026-66308-microsoft-skype-for-business-out-of-bounds-read)
- [Microsoft Skype for Business integer underflow denial of service](https://junglewise.ai/threats/cve-2026-66307-microsoft-skype-for-business-integer-underflow-denial-of-service)