CVE-2025-40776: Birthday Attack against Resolvers supporting ECS

Overview

Severity

High (CVSS 8.6)

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N

Exploit Status

Not Exploited

Patch Tuesday

2026-Aug

Released

2026-08-07

EPSS Score

0.20% (percentile: 9.7%)

Affected Products (2)

Open Source Software

• cbl2 bind 9.16.50-1

Mariner

• azl3 bind 9.20.9-1 on Azure Linux 3.0

Revision History

• 2026-08-07: Information published.