CVE-2025-40777
" BIND Named CNAME Chain Abort Vulnerability"
Description
If a `named` caching resolver is configured with `serve-stale-enable` `yes`, and with `stale-answer-client-timeout` set to `0` (the only allowable value other than `disabled`), and if the resolver, in the process of resolving a query, encounters a CNAME chain involving a specific combination of cached or authoritative records, the daemon will abort with an assertion failure. This issue affects BIND 9 versions 9.20.0 through 9.20.10, 9.21.0 through 9.21.9, and 9.20.9-S1 through 9.20.10-S1.
INFO
Published Date :
July 16, 2025, 6:15 p.m.
Last Modified :
July 17, 2025, 9:15 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Update the affected bind packages.
- Upgrade to the latest available version.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2025-40777.
| URL | Resource |
|---|---|
| https://kb.isc.org/docs/cve-2025-40777 |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2025-40777 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2025-40777
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2025-40777 vulnerability anywhere in the article.
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CybersecurityNews
BIND 9 Vulnerabilities Expose Organizations to Cache Poisoning and DoS Attacks
Two critical vulnerabilities in the BIND 9 DNS resolver software are affecting organizations worldwide, with potential cache poisoning and denial-of-service attacks. The vulnerabilities, identified as ... Read more
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Daily CyberSecurity
ISC Warns of Cache Poisoning and Crash Risks in BIND: What You Need to Know About CVE-2025-40776 and CVE-2025-40777
The Internet Systems Consortium (ISC) has issued two security advisories addressing two high-impact vulnerabilities in BIND, its widely used Domain Name System (DNS) software. The vulnerabilities, tra ... Read more
The following table lists the changes that have been made to the
CVE-2025-40777 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by [email protected]
Jul. 16, 2025
Action Type Old Value New Value Added Description If a `named` caching resolver is configured with `serve-stale-enable` `yes`, and with `stale-answer-client-timeout` set to `0` (the only allowable value other than `disabled`), and if the resolver, in the process of resolving a query, encounters a CNAME chain involving a specific combination of cached or authoritative records, the daemon will abort with an assertion failure. This issue affects BIND 9 versions 9.20.0 through 9.20.10, 9.21.0 through 9.21.9, and 9.20.9-S1 through 9.20.10-S1. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-617 Added Reference https://kb.isc.org/docs/cve-2025-40777