---
id: CVE-2026-27853
title: >-
  An attacker might be able to trigger an out-of-bounds write by sending crafted
  DNS responses to a DNSdist using the DNSQuestion:changeName or
  DNSResponse:changeName methods in custom Lua code
summary: >-
  An attacker might be able to trigger an out-of-bounds write by sending crafted
  DNS responses to a DNSdist using the DNSQuestion:changeName or
  DNSResponse:changeName methods in custom Lua code. In some cases the rewritten
  packet might bec…
severity: medium
cvss: 5.9
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-787
vendor: powerdns
product: dnsdist
affected:
  - 'dnsdist >= 1.9.0, < 1.9.12'
  - 'dnsdist >= 2.0.0, < 2.0.3'
patched:
  - dnsdist 2.0.3
published: '2026-03-31'
updated: '2026-07-25'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-27853'
references:
  - url: >-
      https://www.dnsdist.org/security-advisories/powerdns-advisory-for-dnsdist-2026-02.html
    label: security@open-xchange.com
tags:
  - nvd
epss: 0.01503
epssPercentile: 0.73238
ingestedAt: '2026-07-25T10:53:53.250Z'
---

## Overview

An attacker might be able to trigger an out-of-bounds write by sending crafted DNS responses to a DNSdist using the DNSQuestion:changeName or DNSResponse:changeName methods in custom Lua code. In some cases the rewritten packet might become larger than the initial response and even exceed 65535 bytes, potentially leading to a crash resulting in denial of service.

## Affected

- `dnsdist >= 1.9.0, < 1.9.12`
- `dnsdist >= 2.0.0, < 2.0.3`

## Remediation

Upgrade past the affected range:

- `dnsdist 2.0.3`