CVE-2025-40776

High

Description

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.

SeverityHigh

CVSS8.6

Exploit probability—

ProductBIND 9

PublishedJul 16, 2025

First seenJul 16, 2025

Weakness typeCWE-349CWE-349

How to fix

Vendor advisories

kb.isc.org/docs/cve-2025-40776

Affected products

Product	Affected versions	Fixed in
ISC BIND 9	9.11.3-S1 ≤ v ≤ 9.16.50-S1, 9.18.11-S1 ≤ v ≤ 9.18.37-S1, 9.20.9-S1 ≤ v ≤ 9.20.10-S1	—

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