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2026-007 Critical Vulnerability in Windows Netlogon — CERT-EU-SA2026-007

CERT-EU · CERT-EU · CERT-EU-SA2026-007

ID
CERT-EU-SA2026-007
Date
Activity
Source
CERT-EU
Vendor
CERT-EU
Threat
critical
Exploited
Yes

Summary

On 12 May 2026, Microsoft published a security advisory addressing a critical vulnerability affecting Windows Server when acting as a domain controller. This vulnerability allows an unauthenticated attacker to execute arbitrary code over a network. According to The Centre for Cybersecurity Belgium (CCB), this vulnerability is currently exploited by threat actors. It is strongly recommended updating affected Windows…

Product

Security advisory

What to do

General, cautious steps (verify details in the official source):

  • Prioritize patching or mitigation immediately (treat as actively risky).
  • Identify affected product versions in your inventory and verify whether you are impacted.
  • Apply vendor patches/updates or recommended mitigations as soon as available.
  • Check logs/telemetry for indicators of compromise and suspicious activity.
  • Consider temporary hardening: restrict access, reduce attack surface, and monitor aggressively.
  • Read the official advisory for exact affected versions and remediation steps.

Official advisory

Related advisories