CVE-2026-42002: Concurrency and locking defects in GSS-TSIG

Routine

MEDIUM 5.9REMOTEUPGRADE

CVE-2026-42002 is a medium-severity flaw (CVSS 5.9) affecting authoritative. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Concurrency and locking defects in GSS-TSIG

Why this priority

Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	5.9 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.3% (top 82%)
CISA exploited list	No
Weakness	CWE-364
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-2026-42002?

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

Is CVE-2026-42002 being exploited?

CVE-2026-42002 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-2026-42002 affect?

CVE-2026-42002 affects authoritative. Severity is medium (CVSS 5.9). Concurrency and locking defects in GSS-TSIG

How urgent is CVE-2026-42002?

Priority 30/100. Remotely exploitable, no login, no user action

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References

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