---
id: CVE-2026-19630
title: Amplified resource exhaustion in inbound message processing
summary: >-
  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
  consu…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cvssSource: cna
cwe:
  - CWE-407
vendor: ISC
product: BIND 9
affected:
  - bind_9 >= 9.11.0 <= 9.18.50
  - bind_9 >= 9.20.0 <= 9.20.29
  - bind_9 >= 9.21.0 <= 9.21.26
  - bind_9 >= 9.11.3-S1 <= 9.18.50-S1
  - bind_9 >= 9.20.9-S1 <= 9.20.29-S1
published: '2026-10-21'
updated: '2026-10-21'
sourceUpdated: '2026-10-21T12:41:04.379Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-19630'
references:
  - url: 'https://kb.isc.org/docs/cve-2026-19630'
    label: CVE-2026-19630
  - url: 'https://downloads.isc.org/isc/bind9/9.20.30'
  - url: 'https://downloads.isc.org/isc/bind9/9.21.27'
tags:
  - cve.org
ingestedAt: '2026-10-21T12:48:53.633Z'
---

## Overview

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.

## Affected

- `bind_9 >= 9.11.0 <= 9.18.50`
- `bind_9 >= 9.20.0 <= 9.20.29`
- `bind_9 >= 9.21.0 <= 9.21.26`
- `bind_9 >= 9.11.3-S1 <= 9.18.50-S1`
- `bind_9 >= 9.20.9-S1 <= 9.20.29-S1`

## Remediation

Upgrade to the patched release most closely related to your current version of BIND 9: 9.20.30, 9.21.27, or 9.20.30-S1.

### Workarounds

No workarounds known.