---
id: CVE-2026-96405
title: >-
  Aggregate DNS name chained pointer decompression work leads to degradation of
  service.
summary: >-
  NLnet Labs Unbound up to and including version 1.26.1 limits
  compression-pointer traversal for each individual domain-name operation but
  has no aggregate inbound decompression-work budget. Many chained compression
  pointers in a message r…
severity: medium
cvss: 5.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'
cvssSource: cna
cwe:
  - CWE-770
vendor: NLnet Labs
product: Unbound
affected:
  - Unbound < 1.26.2
published: '2026-10-21'
updated: '2026-10-21'
sourceUpdated: '2026-10-21T08:57:26.986Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-96405'
references:
  - url: 'https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-96405.txt'
tags:
  - cve.org
ingestedAt: '2026-10-21T09:46:15.398Z'
---

## Overview

NLnet Labs Unbound up to and including version 1.26.1 limits compression-pointer traversal for each individual domain-name operation but has no aggregate inbound decompression-work budget. Many chained compression pointers in a message results in a lot of CPU usage following them. A malicious actor with recursive-query access and control of an ordinarily delegated authority that serves specially crafted replies can exploit the vulnerability and degrade Unbound's general performance.

## Affected

- `Unbound < 1.26.2`

## Remediation

This issue is fixed starting with version 1.26.2