Vulnerability · Published Sep 8, 2026 · Assigned by microsoft
CVE-2026-66303Skype for Business and Lync Denial of Service Vulnerability
Medium 6.5
In plain English
A medium-severity null pointer dereference in Skype for Business Server 2015 CU13 from Microsoft. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.1% (higher than 67% of all known vulnerabilities).
Severity (CVSS 3.1)6.5Medium
Exploit odds (30 days)1.1%top 33.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
Null pointer dereference in Skype for Business allows an authorized attacker to deny service over a network.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Microsoft | Skype for Business Server 2015 CU13 | 9319.0 – before 6.0.9319.885 |
| Microsoft | Skype for Business Server 2019 CU8 | 2046.0 – before 7.0.2046.569 |
| Microsoft | Skype for Business Server Subscription Edition CU1 | 2046.0 – before 7.0.2046.879 |
Weakness: CWE-476 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C
References
- Skype for Business and Lync Denial of Service Vulnerability vendor-advisory, patch