home / blog
2026-10-13 · high
Windows DHCP Client: use-after-free over an adjacent network (CVE-2026-70250)
Use-after-free in the Windows DHCP client, code execution from an adjacent network, CVSS 3.1 8.8. Install the Microsoft October 2026 patch.
On 13 October 2026 Microsoft published the record for CVE-2026-70250, a use-after-free in the Windows DHCP client. According to NVD, an unauthorised attacker on an adjacent network can execute code. The CVSS v3.1 score is 8.8, with an adjacent-network vector.
The adjacent vector means the risk is concentrated on shared local networks, such as offices, data centres or wireless segments. An isolated machine is less exposed, but should not be neglected.
Install the Microsoft October 2026 patch on Windows machines, prioritising servers and endpoints on shared networks. The NVD record rates the severity as high; some secondary sources call it critical, but the official reference remains NVD.
At a glance
- What
- Use-after-free in the Windows DHCP client. An unauthorised attacker on an adjacent network can execute code.
- Severity
- CVSS v3.1 8.8 (high) according to NVD, with an adjacent-network vector (AV:A). Some secondary sources call it critical: NVD rates it high.
- Cause
- Use-after-free (CWE-416) combined with a race condition (CWE-362).
- Fix
- Microsoft patch from October 2026, to be confirmed on the MSRC bulletin for the affected builds.
- Action
- Install the patch on Windows machines, prioritising servers and endpoints connected to shared network segments.
Sources: NVD, CVE-2026-70250 · Microsoft MSRC, CVE-2026-70250