Vulnerability · Published Oct 13, 2026 · Assigned by microsoft
CVE-2026-88099Windows Failover Cluster Denial of Service Vulnerability
Medium 5.9
In plain English
A medium-severity security flaw in Windows Server 2019 from Microsoft. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.8% (higher than 57% of all known vulnerabilities).
Severity (CVSS 3.1)5.9Medium
Exploit odds (30 days)0.8%top 42.7% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
Uncaught exception in Windows Failover Cluster allows an unauthorized attacker to deny service over a network.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Microsoft | Windows Server 2019 | 10.0.17763.0 – before 10.0.17763.9376 |
| Microsoft | Windows Server 2019 (Server Core installation) | 10.0.17763.0 – before 10.0.17763.9376 |
| Microsoft | Windows Server 2022 | 10.0.20348.0 – before 10.0.20348.5761 |
| Microsoft | Windows Server 2025 | 10.0.26100.0 – before 10.0.26100.33650 |
| Microsoft | Windows Server 2025 (Server Core installation) | 10.0.26100.0 – before 10.0.26100.33650 |
Weakness: CWE-248 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C
References
- Windows Failover Cluster Denial of Service Vulnerability vendor-advisory, patch