What is CVE-2026-66303?

CVE-2026-66303 is a medium-severity vulnerability in Microsoft Skype For Business Server 2015 Cu13, classified under NULL Pointer Dereference. CVSS score: 6.5/10. Published 2026-09-08.

How severe is CVE-2026-66303?

Medium severity. CVSS v3 base score is 6.5 out of 10.

NULL pointer dereference in Microsoft Skype For Business Server 2015 Cu13

CVE-2026-66303

Null pointer dereference in Skype for Business allows an authorized attacker to deny service over a network.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

Affected products

Microsoft Skype For Business Server 2015 Cu13

Weakness classification (CWE)

CWE-476 — NULL Pointer Dereference

References

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

Frequently asked questions

What is CVE-2026-66303?: CVE-2026-66303 is a medium-severity vulnerability in Microsoft Skype For Business Server 2015 Cu13, classified under NULL Pointer Dereference. CVSS score: 6.5/10. Published 2026-09-08.
How severe is CVE-2026-66303?: Medium severity. CVSS v3 base score is 6.5 out of 10.