# CVE-2026-66308: Microsoft Skype for Business out-of-bounds read

Source: https://junglewise.ai/threats/cve-2026-66308-microsoft-skype-for-business-out-of-bounds-read  
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-2026-66308 · Severity: medium · CVSS 6.5 · Published 2026-09-08

Skype for Business contains an out-of-bounds read vulnerability that allows an authorized attacker to cause a denial of service condition. An attacker with valid credentials can trigger a network-based attack that crashes the application or makes it unavailable to users.

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-2026-66308 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-66308 being exploited in the wild.

**How severe is CVE-2026-66308?** Medium severity, with a CVSS score of 6.5, published 8 September 2026.

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

**Is there a fix for CVE-2026-66308?** 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-2026-66308 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-66308?** 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

An out-of-bounds read vulnerability exists in Microsoft Skype for Business, allowing an authenticated attacker to trigger a denial of service condition. The vulnerability requires network access and valid authentication credentials. By sending a specially crafted network message, an attacker can cause the application to read memory outside of allocated bounds, leading to application crash or service interruption. A patch is available from Microsoft.

## Affected products

- Microsoft Skype for Business

## Timeline

- 2026-09-08: disclosed: CVE-2026-66308 published

## References

- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-66308](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-66308)

## 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 integer underflow denial of service](https://junglewise.ai/threats/cve-2026-66307-microsoft-skype-for-business-integer-underflow-denial-of-service)
- [Microsoft Skype for Business information disclosure in error messages](https://junglewise.ai/threats/cve-2026-66306-microsoft-skype-for-business-information-disclosure-in-error)