How severe is CVE-2026-42390?

CVE-2026-42390 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2026-42390 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-42390?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-42390 have an EU (EUVD) identifier?

Yes. CVE-2026-42390 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-39359.

When was CVE-2026-42390 published?

CVE-2026-42390 was published on 2026-06-25.

CVE-2026-42390

CVE-2026-42390 is a medium-severity vulnerability with a CVSS 3.x base score of 5.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-20.

Key facts

Severity: Medium (CVSS 3.x base score 5.3)
EPSS exploit prediction: 0% (12th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-39359
Weakness: CWE-20
Published: 2026-06-25
Last modified: 2026-06-25

Description

An invalid zone might pass ZONEMD validation while it should not. This is only relevant if ZoneToCache is configured with ZONEMD validation.

Frequently asked questions

What is CVE-2026-42390?: An invalid zone might pass ZONEMD validation while it should not. This is only relevant if ZoneToCache is configured with ZONEMD validation.
How severe is CVE-2026-42390?: CVE-2026-42390 has a CVSS 3.x base score of 5.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2026-42390 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-42390?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-42390 have an EU (EUVD) identifier?: Yes. CVE-2026-42390 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-39359.
When was CVE-2026-42390 published?: CVE-2026-42390 was published on 2026-06-25.

References

https://docs.powerdns.com/recursor/security-advisories/powerdns-advisory-powerdns-2026-08.html

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