What is CVE-2026-19630?

CVE-2026-19630 is a high-severity vulnerability in Isc Bind 9, classified under Inefficient Algorithmic Complexity. CVSS score: 7.5/10. Published 2026-10-21.

How severe is CVE-2026-19630?

High severity. CVSS v3 base score is 7.5 out of 10.

Vulnerability in Isc Bind 9

CVE-2026-19630

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.

Published 2026-10-21 · last modified 2026-10-21.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Isc Bind 9

Weakness classification (CWE)

CWE-407 — Inefficient Algorithmic Complexity

References

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

Frequently asked questions

What is CVE-2026-19630?: CVE-2026-19630 is a high-severity vulnerability in Isc Bind 9, classified under Inefficient Algorithmic Complexity. CVSS score: 7.5/10. Published 2026-10-21.
How severe is CVE-2026-19630?: High severity. CVSS v3 base score is 7.5 out of 10.