Vulnerability · Published Jun 25, 2026 · Assigned by OX
CVE-2026-42389Reject more queries with invalid header values
Medium 5.3
In plain English
A medium-severity improper input validation in Recursor from PowerDNS. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 23% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)5.3Medium
Exploit odds (30 days)0.3%top 77.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
This fix provides extra hardening for the 5.4.x branch by doing extra validation of incoming answers from authoritative servers.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:14 | pdns-recursor | 5.4.3-1 | DEBIAN-CVE-2026-42389 |
| Ubuntu:24.04:LTS | pdns-recursor | no fix listed | UBUNTU-CVE-2026-42389 |
| Ubuntu:25.10 | pdns-recursor | no fix listed | UBUNTU-CVE-2026-42389 |
| Ubuntu:26.04:LTS | pdns-recursor | no fix listed | UBUNTU-CVE-2026-42389 |
| Ubuntu:26.10 | pdns-recursor | no fix listed | UBUNTU-CVE-2026-42389 |
Affected products (as reported)
Weakness: CWE-20 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N