---
id: CVE-2026-97313
title: >-
  Specific RPZ configurations and query patterns may result in an unexpected
  exit
summary: >-
  A recursive BIND server that receives a query with recursion desired (RD=1)
  followed by a non-recursive query (RD=0) may exit with an assertion failure,
  resulting in a denial of service. To be vulnerable, the BIND server must allow
  recur…
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-617
vendor: ISC
product: BIND 9
affected:
  - bind_9 >= 9.16.0 <= 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
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-10-21T15:18:26.657640Z'
published: '2026-10-21'
updated: '2026-10-21'
sourceUpdated: '2026-10-21T17:19:13.974Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-97313'
references:
  - url: 'https://kb.isc.org/docs/cve-2026-97313'
    label: CVE-2026-97313
  - url: 'https://downloads.isc.org/isc/bind9/9.20.30'
  - url: 'https://downloads.isc.org/isc/bind9/9.21.27'
tags:
  - cve.org
ingestedAt: '2026-10-21T13:57:01.187Z'
---

## Overview

A recursive BIND server that receives a query with recursion desired (RD=1) followed by a non-recursive query (RD=0) may exit with an assertion failure, resulting in a denial of service. To be vulnerable, the BIND server must allow recursive queries and have at least two RPZ zones configured: one with the default setting of "recursive-only yes", and the other with "recursive-only no".
This issue affects BIND 9 versions 9.16.0 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 >= 9.16.0 <= 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.