CVE-2026-27853 MEDIUM

CVE-2026-27853: Out-of-bounds write when rewriting large DNS packets

Vendor Powerdns
Product DNSdist
Published March 31, 2026
Last update March 31, 2026

CVSS base score

5.9/10
Attack vector Network
Attack complexity High
Privileges required None
User interaction None
Confidentiality None
Integrity None

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

What the vulnerability does

01Description

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.

Key dates

02Disclosure timeline

March 31, 2026 CVE published
March 31, 2026 Record updated