CVE-2025-40776 - CVE House
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Status published High CVE-2025-40776

Birthday Attack against Resolvers supporting ECS

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.

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

The following person or organization is credited with identifying this vulnerability, as recorded in the NVD database:

  • ISC would like to thank Xiang Li from AOSP Lab of Nankai University for bringing this vulnerability to our attention.

References

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Affected Vendor

Affected Software

BIND 9
Vulnerable Versions:
9.11.3-S1, 9.18.11-S1, 9.20.9-S1, 9.0.0

Timeline

Official Publish: July 16th, 2025
Last Modified: July 22nd, 2025
Added to House: July 22nd, 2026

CVSS Vectors

V3: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N

Weaknesses (CWE)

CWE-349

MITRE ATT&CK TTPs

No associated TTPs found for this vulnerability.