CVE-2026-70087: Local DNS Server Security Feature Bypass

What happened

A local privilege escalation flaw was identified in Microsoft DNS Server. The vulnerability allows an attacker who already has local access to bypass a built‑in security feature, enabling further compromise.

Impact

Systems running vulnerable versions of Windows Server DNS can be manipulated to execute arbitrary code or modify zone data. The flaw does not require network exposure; it is exploitable from the local machine.

Mitigation

• Apply the latest cumulative update for Windows Server (KBxxxxxx) that addresses CVE‑2026‑70087.
• Restrict local administrator rights; enforce least‑privilege for DNS service accounts.
• Enable DNSSEC and enforce signed zones to reduce the risk of tampering.

What to do

Check the DNS Server version and apply the patch immediately. Review local accounts with administrative privileges and audit DNS logs for abnormal zone changes. Consider deploying a host‑based intrusion detection system to alert on privilege‑escalation attempts.