Cache-Poisoning Vulnerability in BIND 9 by ISC
CVE-2025-40776

8.6HIGH

Key Information:

Vendor

Isc
Status
Bind 9
Vendor
CVE Published:
16 July 2025

Badges

👾 Exploit Exists

What is CVE-2025-40776?

A vulnerability has been identified in BIND 9, where a caching resolver configured to utilize EDNS Client Subnet options is susceptible to cache-poisoning attacks. This can lead to the manipulation of DNS cache entries, allowing attackers to respond to queries with malicious data. Users of affected BIND 9 versions should assess their configurations and apply the necessary updates to mitigate potential risks.

Affected Version(s)

BIND 9 9.11.3-S1 <= 9.16.50-S1

BIND 9 9.18.11-S1 <= 9.18.37-S1

BIND 9 9.20.9-S1 <= 9.20.10-S1

References

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

CVSS V3.1

Score:
8.6
Severity:
HIGH
Confidentiality:
None
Integrity:
High
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Changed

Timeline

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

Credit

ISC would like to thank Xiang Li from AOSP Lab of Nankai University for bringing this vulnerability to our attention.
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CVE-2025-40776 : Cache-Poisoning Vulnerability in BIND 9 by ISC