Birthday Attack against Resolvers supporting ECS

Scope

What the vendor says is affected

• cbl2 bind 9.16.50-1
• azl3 bind 9.20.9-1 on Azure Linux 3.0

Timeline

When this advisory changed

1. Aug 7, 2026 at 1:01 AM UTC
   Published by Microsoft Security Response Center

   The publication date reported by the vendor.

2. Sep 27, 2026 at 11:11 PM UTC
   Added to SecurityAlert

   We collected the advisory from the official source.

Vulnerabilities

CVEs named in this advisory

CVE-2025-40776View CVSS, KEV, EPSS, and threat context