Vulnerability · Published Jul 16, 2025 · Assigned by isc
CVE-2025-40776Birthday Attack against Resolvers supporting ECS
High 8.6
In plain English
A high-severity security flaw in BIND 9 from ISC. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 13% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)8.6High
Exploit odds (30 days)0.2%top 86.6% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.22 | bind | 9.20.11-r0 | ALPINE-CVE-2025-40776 |
| Alpine:v3.23 | bind | 9.20.11-r0 | ALPINE-CVE-2025-40776 |
| Alpine:v3.24 | bind | 9.20.11-r0 | ALPINE-CVE-2025-40776 |
Affected products (as reported)
Weakness: CWE-349 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N
References
- CVE-2025-40776 vendor-advisory