CVE-2025-40776 — HIGH (8.6)

Vulnerability 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.

CVSS Score

8.6

HIGH

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

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

CHANGED

Confidentiality

NONE

Integrity

HIGH

Availability

NONE

Related Weaknesses (CWE)

CWE-349

References

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

FAQ

What is CVE-2025-40776?

CVE-2025-40776 is a vulnerability with a CVSS score of 8.6 (HIGH). 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...

How severe is CVE-2025-40776?

CVE-2025-40776 has been rated HIGH with a CVSS base score of 8.6/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2025-40776?

Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.