CVE-2025-40776 HIGH

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

Vendor Isc
Product BIND 9
Weakness CWE-349
Published July 16, 2025
Last update July 22, 2025
View on NVD All CVEs

CVSS base score

8.6/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality None
Integrity High

CVSS vector

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

What the vulnerability does

01Description

A `named` caching resolver that is configured to send ECS (EDNS Client Subnet) options may be vulnerable to a cache-poisoning attack. This issue affects BIND 9 versions 9.11.3-S1 through 9.16.50-S1, 9.18.11-S1 through 9.18.37-S1, and 9.20.9-S1 through 9.20.10-S1.

Key dates

02Disclosure timeline

July 16, 2025 CVE published
July 22, 2025 Record updated