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CVE-2026-19666 is a vulnerability in ISC BIND
Published on September 16, 2026
Use-after-free in query_addnoqnameproof() via the DNS64 filter64 path
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.
Vulnerability Analysis
CVE-2026-19666 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a high impact on availability.
Weakness Type
What is a Dangling pointer Vulnerability?
Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.
CVE-2026-19666 has been classified to as a Dangling pointer vulnerability or weakness.
Products Associated with CVE-2026-19666
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Affected Versions
ISC BIND 9:- Version 9.11.0, <= 9.18.50 is affected.
- Version 9.20.0, <= 9.20.27 is affected.
- Version 9.21.0, <= 9.21.25 is affected.
- Version 9.11.3-S1, <= 9.18.50-S1 is affected.
- Version 9.20.9-S1, <= 9.20.27-S1 is affected.