CVE-2026-42389

Reject more queries with invalid header values

5.3 MediumFix available

This fix provides extra hardening for the 5.4.x branch by doing extra validation of incoming answers from authoritative servers.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: None
Integrity: Low
Availability: None

Exploit likelihood

0.30%Up 0.1 points since Jun 26, 2026

What each source reports

CVE List Score used 5.3

Reject more queries with invalid header values

This fix provides extra hardening for the 5.4.x branch by doing extra validation of incoming answers from authoritative servers.

Record: CVE-2026-42389
CVSS 3.1: 5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Weakness: CWE-20
Updated: 2026-11-02

EUVDEUVD-2026-39388 5.3

This fix provides extra hardening for the 5.4.x branch by doing extra validation of incoming answers from authoritative servers.

Record: EUVD-2026-39388
CVSS 3.1: 5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Updated: 2026-11-02

GitHub AdvisoriesGHSA-hrq7-vr6r-5mvq 5.3

This fix provides extra hardening for the 5.4.x branch by doing extra validation of incoming...

This fix provides extra hardening for the 5.4.x branch by doing extra validation of incoming answers from authoritative servers.

Record: GHSA-hrq7-vr6r-5mvq
CVSS 3.1: 5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Weakness: CWE-20
Updated: 2026-11-02

NVD 5.3

This fix provides extra hardening for the 5.4.x branch by doing extra validation of incoming answers from authoritative servers.

Record: CVE-2026-42389
CVSS 3.1: 5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Weakness: CWE-20
Updated: 2026-11-02

OSV 5.3

Reject more queries with invalid header values

This fix provides extra hardening for the 5.4.x branch by doing extra validation of incoming answers from authoritative servers.

Record: CVE-2026-42389
CVSS 3.1: 5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Updated: 2026-11-02

OSVDEBIAN-CVE-2026-42389 5.3

This fix provides extra hardening for the 5.4.x branch by doing extra validation of incoming answers from authoritative servers.

Record: DEBIAN-CVE-2026-42389
CVSS 3.1: 5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Updated: 2026-11-02

OSVUBUNTU-CVE-2026-42389 5.3

This fix provides extra hardening for the 5.4.x branch by doing extra validation of incoming answers from authoritative servers.

Record: UBUNTU-CVE-2026-42389
CVSS 3.1: 5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Updated: 2026-11-02

Affected products

powerdns recursor

Affected packages

Affected packages
Package	Affected	Fixed
`pdns-recursor` Debian:14	before 5.4.3-1, plus listed versions 5.2.4-25.2.5-15.3.0-15.3.0-25.3.0-3 Show 12 moreShow less 5.3.0-45.3.0-55.3.1-15.3.3-15.3.4-15.3.4-25.3.5-15.4.0-15.4.1-15.4.1-25.4.2-15.4.2-2	5.4.3-1
`pdns-recursor` Ubuntu:Pro:16.04:LTS	All versions, plus listed versions 3.7.3-14.0.0~alpha1-14.0.0~alpha1-24.0.0~alpha2-24.0.0~alpha2-2ubuntu0.14.0.0~alpha2-2ubuntu0.1+esm1	None known
`pdns-recursor` Ubuntu:Pro:18.04:LTS	All versions, plus listed versions 4.0.6-14.0.6-1build14.0.7-14.1.1-14.1.1-1build14.1.1-24.1.1-2ubuntu0.1~esm1	None known
`pdns-recursor` Ubuntu:Pro:20.04:LTS	All versions, plus listed versions 4.2.0-64.2.1-14.2.1-1build14.2.1-1build24.2.1-1ubuntu0.1~esm1	None known
`pdns-recursor` Ubuntu:Pro:22.04:LTS	All versions, plus listed versions 4.4.2-34.6.0-1ubuntu14.6.0-1ubuntu1+esm1	None known
`pdns-recursor` Ubuntu:24.04:LTS	All versions, plus listed versions 4.9.0-24.9.1-44.9.2-14.9.2-1build14.9.2-24.9.3-14.9.3-1build24.9.3-1build3	None known
`pdns-recursor` Ubuntu:25.10	All versions, plus listed versions 5.2.0-55.2.2-15.2.2-25.2.4-25.2.4-2build2	None known
`pdns-recursor` Ubuntu:26.10	All versions, plus listed versions 5.3.5-15.4.3-15.4.5-1	None known
`pdns-recursor` Ubuntu:26.04:LTS	All versions, plus listed versions 5.2.4-2build25.3.1-15.3.3-15.3.4-15.3.4-1build15.3.4-25.3.5-1	None known

History

History
Recorded	Changed	Sources
Nov 2, 2026	first indexed	CVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-42389 is a medium vulnerability (CVSS 5.3) in Powerdns Recursor, published June 25, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.30%, the 22nd percentile. Fixed in pdns-recursor 5.4.3-1.

References

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