CVE-2026-42396: Insufficient Validation of Member Zone Data May Cause Catalog Zone Transfer to Fail

Routine

MEDIUM 4.9UPGRADE

CVE-2026-42396 is a medium-severity flaw (CVSS 4.9) affecting authoritative. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Insufficient Validation of Member Zone Data May Cause Catalog Zone Transfer to Fail

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	4.9 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	High
User interaction	None
EPSS exploit chance	0.4% (top 71%)
CISA exploited list	No
Weakness	CWE-94
Published	2026-05-21
Last modified	2026-07-23

Publisher (CNA): Open-Xchange · Vendor: powerdns

Last updated 2026-07-23 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-21 10:16 UTCPublished CVE record published
2026-07-23 16:10 UTCUpdated Record last modified

powerdns authoritative UPGRADE

Affected: >= 4.7.0 and < 4.9.15 · >= 5.0.0 and < 5.0.5

Fixed in: 4.9.15, 5.0.5

Safe to downgrade to: a release before 4.7.0

1. Check installed version

apt-cache policy authoritative || rpm -q authoritative || authoritative --version

2. UPGRADE to 4.9.15 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade authoritative

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade authoritative

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 4.7.0 (Debian / Ubuntu)

apt-cache madison authoritative sudo apt install authoritative=<VERSION_BEFORE_4.7.0> sudo apt-mark hold authoritative

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list authoritative sudo dnf downgrade authoritative-<VERSION_BEFORE_4.7.0> sudo dnf versionlock add authoritative

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-42396?

authoritative: upgrade to 4.9.15, 5.0.5. Exact commands for each OS are on this page.

Is CVE-2026-42396 being exploited?

CVE-2026-42396 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-42396 affect?

CVE-2026-42396 affects authoritative. Severity is medium (CVSS 4.9). Insufficient Validation of Member Zone Data May Cause Catalog Zone Transfer to Fail

How urgent is CVE-2026-42396?

Priority 24/100. No elevated risk signals yet.

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References

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