CVE-2026-66308 Skype for Business and Lync Denial of Service Vulnerability
An authorized attacker can cause a denial of service in Skype for Business Server via an out-of-bounds read vulnerability.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-66308?
CVE-2026-66308 is a medium-severity denial of service vulnerability in Microsoft Skype for Business Server 2015 CU13, published on 8 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Out-of-bounds read in Skype for Business allows an authorized attacker to deny service over a network.
Weakness: CWE-125
Which versions are affected by CVE-2026-66308?
It affects 2 products.
Products include Microsoft Skype for Business Server, Microsoft Skype for Business Server Subscription Edition.
How do I fix CVE-2026-66308?
No fix has been published for CVE-2026-66308 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-66308 being exploited?
There is no known exploitation of CVE-2026-66308 in the wild and no public exploit code.
Other vulnerabilities in Microsoft Skype for Business Server 2015 CU13
- CVE-2023-41763 Microsoft Skype for Business Privilege Escalation
- CVE-2026-66302 Skype for Business Remote Code Execution Vulnerability
- CVE-2026-69646 Skype for Business Spoofing Vulnerability
- CVE-2026-66304 Skype for Business Information Disclosure Vulnerability
- CVE-2026-66307 Skype for Business and Lync Denial of Service Vulnerability
Sources
Also known as GHSA-hwrf-3w89-xf2g.