What is CVE-2026-66302?

CVE-2026-66302 is a critical-severity vulnerability in Microsoft Skype For Business Server 2015 Cu13, classified under External Control of File Name or Path. CVSS score: 9.8/10. Published 2026-09-08.

How severe is CVE-2026-66302?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Vulnerability in Microsoft Skype For Business Server 2015 Cu13

CVE-2026-66302

External control of file name or path in Skype for Business allows an unauthorized attacker to execute code over a network.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Microsoft Skype For Business Server 2015 Cu13

Weakness classification (CWE)

CWE-73 — External Control of File Name or Path

References

secure@microsoft.com (vendor-advisory, patch)

Frequently asked questions

What is CVE-2026-66302?: CVE-2026-66302 is a critical-severity vulnerability in Microsoft Skype For Business Server 2015 Cu13, classified under External Control of File Name or Path. CVSS score: 9.8/10. Published 2026-09-08.
How severe is CVE-2026-66302?: Critical severity. CVSS v3 base score is 9.8 out of 10.