Quick answers
- Is CVE-2026-77890 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-77890 being exploited in the wild.
- How severe is CVE-2026-77890?
- High severity, with a CVSS score of 7.5, published 8 September 2026.
- Which products and versions are affected?
- Microsoft Windows DHCP Server <UNKNOWN>.
- Is there a fix for CVE-2026-77890?
- 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-2026-77890 attacked?
- It is attacked over the network, in an operating system.
- Am I affected by CVE-2026-77890?
- 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 exists in Windows DHCP Server where resources are accessed using incompatible types, violating memory safety assumptions. The vulnerability is triggered over the network without requiring authentication or user interaction. An attacker can send specially crafted DHCP protocol packets to cause a denial of service by crashing the DHCP Server process. The attack vector is network-based and reaches any system running the vulnerable DHCP Server component.
Affected products
- Microsoft Windows DHCP Server <UNKNOWN>
Timeline
- 2026-09-08: disclosed