Vulnerability details

CVE-2026-19630

ISC BIND 9

Amplified resource exhaustion in inbound message processing

CVSS 3.1

7.5High

Official 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.

CVSS scores

Score	Version	Source	Vector
7.5High	3.1	CVEProject cvelistV5 (CNA) (isc)	`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`

Affected products

Vendor	Product	Versions	Source
ISC	BIND 9	9.11.0 ≤ v ≤ 9.18.50	CVEProject cvelistV5 (CNA)
ISC	BIND 9	9.11.3-S1 ≤ v ≤ 9.18.50-S1	CVEProject cvelistV5 (CNA)
ISC	BIND 9	9.20.0 ≤ v ≤ 9.20.29	CVEProject cvelistV5 (CNA)
ISC	BIND 9	9.20.9-S1 ≤ v ≤ 9.20.29-S1	CVEProject cvelistV5 (CNA)
ISC	BIND 9	9.21.0 ≤ v ≤ 9.21.26	CVEProject cvelistV5 (CNA)

References and advisories

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

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Details

Published: 2026-10-21
Last updated: 2026-10-21
State: Published
Assigner (CNA): isc

Exploit prediction (EPSS)

0.44%

Probability of exploitation in 30 days

39.1%

Percentile (among all CVEs)

SSVC assessment (CISA)

Automatable: Yes
Exploitation: None
Technical impact: Partial

Weaknesses (CWE)

CWE-407
Inefficient Algorithmic Complexity