CVE-2026-19662

qpcache NOQNAME proof use-after-free crashes recursive resolver

State: Published
Severity: 5.9 Medium
Published: Sep 16, 2026
Updated: Sep 17, 2026
Reserved: Aug 12, 2026

Description

An attacker may be able to cause a `named` resolver to abort. The attack requires inducing the victim resolver to send multiple queries for a DNSSEC-signed zone hosted by an authoritative server under the control of the attacker. If the auth responds with a particular sequence of crafted answers, and those answers arrive in a particular order with particular timing, the `named` resolver will encounter a use-after-free bug, and abort. This issue affects BIND 9 versions 9.11.0 through 9.18.50, 9.20.0 through 9.20.27, 9.11.3-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.27-S1.

Scores

CVSS	Score	Vector	Source
3.1	5.9 Medium	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H	isc

Weaknesses

CWE-416 Use After Free

Affected Products

Product	Versions
BIND 9ISC	9.11.0 through 9.18.50Affected 9.20.0 through 9.20.27Affected 9.11.3-S1 through 9.18.50-S1Affected 9.20.9-S1 through 9.20.27-S1Affected

References

CVE-2026-19662vendor-advisory
https://downloads.isc.org/isc/bind9/9.20.29patch

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