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Vulnerability · Published Mar 31, 2026 · Assigned by OX

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

Medium 5.9

In plain English

A medium-severity out-of-bounds write in DNSdist from PowerDNS. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 44% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.9Medium
Exploit odds (30 days)0.5%top 56.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

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 packages & fixed versions

EcosystemPackageFixed inAdvisory
Alpine:v3.23dnsdist2.0.4-r0ALPINE-CVE-2026-27853
Alpine:v3.24dnsdist2.0.4-r0ALPINE-CVE-2026-27853
Debian:12dnsdistno fix listedDEBIAN-CVE-2026-27853
Debian:13dnsdist1.9.14-0+deb13u1DEBIAN-CVE-2026-27853
Debian:14dnsdist2.0.3-1DEBIAN-CVE-2026-27853
Ubuntu:25.10dnsdistno fix listedUBUNTU-CVE-2026-27853
Ubuntu:26.04:LTSdnsdistno fix listedUBUNTU-CVE-2026-27853
Ubuntu:26.10dnsdistno fix listedUBUNTU-CVE-2026-27853

Affected products (as reported)

VendorProductVersions
PowerDNS DNSdist 1.9.0 – before 1.9.122.0.0 – before 2.0.3

Weakness: CWE-787 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

References