Quick answers
- Is CVE-2026-77889 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-77889 being exploited in the wild.
- How severe is CVE-2026-77889?
- High severity, with a CVSS score of 7.5, published 8 September 2026.
- Which products and versions are affected?
- Microsoft Windows DHCP Server multiple versions.
- Is there a fix for CVE-2026-77889?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-77889 attacked?
- It is attacked over the network, in an operating system.
- Am I affected by CVE-2026-77889?
- Check whether you run Microsoft Windows DHCP Server at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
A type confusion vulnerability (CWE-843) in Windows DHCP Server allows an attacker to access memory resources using an incompatible type, triggering a denial of service condition. The vulnerability is network-reachable and requires no authentication or user interaction. An attacker can send a specially crafted DHCP message to crash the DHCP Server service, preventing legitimate clients from obtaining IP addresses. A patch is available from Microsoft.
Affected products
- Microsoft Windows DHCP Server multiple versions
Timeline
- 2026-09-08: disclosed