7.5
HIGH CVSS 3.1
CVE-2026-19666
Use-after-free in query_addnoqnameproof() via the DNS64 filter64 path
Description

On a resolver configured to use ``dns64``, if an applicable answer from the authoritative server is malformed in a specific way, the resolver `named` process will exit unexpectedly. This issue affects BIND 9 versions 9.11.0 through 9.18.50, 9.20.0 through 9.20.27, 9.21.0 through 9.21.25, 9.11.3-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.27-S1.

INFO

Published Date :

Sept. 16, 2026, 3:17 p.m.

Last Modified :

Sept. 16, 2026, 3:17 p.m.

Remotely Exploit :

Yes !
Affected Products

The following products are affected by CVE-2026-19666 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Isc bind
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 HIGH [email protected]
Solution
Update BIND 9 to a patched version to prevent unexpected process exits.
  • Update BIND 9 to a non-vulnerable version.
  • Apply vendor-provided patches for BIND 9.
  • Ensure DNS64 configurations are validated.
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-2026-19666.

URL Resource
https://downloads.isc.org/isc/bind9/9.20.29
https://downloads.isc.org/isc/bind9/9.21.26
https://kb.isc.org/docs/cve-2026-19666
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-19666 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-2026-19666 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-2026-19666 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2026-19666 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.

  • New CVE Received by [email protected]

    Sep. 16, 2026

    Action Type Old Value New Value
    Added Description On a resolver configured to use ``dns64``, if an applicable answer from the authoritative server is malformed in a specific way, the resolver `named` process will exit unexpectedly. This issue affects BIND 9 versions 9.11.0 through 9.18.50, 9.20.0 through 9.20.27, 9.21.0 through 9.21.25, 9.11.3-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.27-S1.
    Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
    Added CWE CWE-416
    Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/19xxx/CVE-2026-19666.json">CVE-2026-19666</a>
    Added Reference https://downloads.isc.org/isc/bind9/9.20.29
    Added Reference https://downloads.isc.org/isc/bind9/9.21.26
    Added Reference https://kb.isc.org/docs/cve-2026-19666
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.