Microsoft Exchange Server Denial of Service Vulnerability

Summary

Inefficient algorithmic complexity in Microsoft Exchange Server allows an unauthorized attacker to deny service over a network.

Products covered

• Microsoft Exchange Server Subscription Edition RTM

Remediation

Install KB5133453.

Vendor-listed fixes

• 15.02.2562.057

CVEs in this advisory 1

CVE-2026-118153

Updates

1. Nov 10, 2026 at 8:00 AM UTC
   Published by Microsoft Security Response Center

   The publication date reported by the vendor.

2. Nov 10, 2026 at 8:15 PM UTC
   Added to SecurityAlert

   We collected the advisory from the official source.