CVE-2026-19666

High

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.

SeverityHigh

CVSS7.5

Exploit probability—

ProductBIND 9

PublishedSep 16, 2026

First seenSep 16, 2026

Weakness typeCWE-416Use after free

How to fix

Patches

Vendor advisories

kb.isc.org/docs/cve-2026-19666

Affected products

Product	Affected versions	Fixed in
ISC BIND 9	9.11.0 ≤ v ≤ 9.18.50, 9.20.0 ≤ v ≤ 9.20.27, 9.21.0 ≤ v ≤ 9.21.25, 9.11.3-S1 ≤ v ≤ 9.18.50-S1, 9.20.9-S1 ≤ v ≤ 9.20.27-S1	—

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