CVE-2026-19630

Amplified resource exhaustion in inbound message processing

State: Published
Severity: 7.5 High
Published: Oct 21, 2026
Updated: Oct 21, 2026
Reserved: Aug 12, 2026

Description

In a BIND resolver, inbound DNS protocol messages with a particular structure will result in additional processing, with no limit imposed by BIND. A DNS message with a maliciously large number of such structures will cause BIND to consume disproportionate amounts of CPU time and memory during processing. This issue affects BIND 9 versions 9.11.0 through 9.18.50, 9.20.0 through 9.20.29, 9.21.0 through 9.21.26, 9.11.3-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.29-S1.

Scores

CVSS	Score	Vector	Source
3.1	7.5 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	isc

Weaknesses

CWE-407 Inefficient Algorithmic Complexity

Affected Products

Product	Versions
BIND 9ISC	9.11.0 through 9.18.50Affected 9.20.0 through 9.20.29Affected 9.21.0 through 9.21.26Affected 9.11.3-S1 through 9.18.50-S1Affected 9.20.9-S1 through 9.20.29-S1Affected

References

CVE-2026-19630vendor-advisory
https://downloads.isc.org/isc/bind9/9.20.30patch
https://downloads.isc.org/isc/bind9/9.21.27patch

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