Is CVE-2026-42387 in the CISA KEV catalog?

No. CVE-2026-42387 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-42387?

CVE-2026-42387 has a CVSS v3 base score of 5.9 (MEDIUM).

What is the EPSS score for CVE-2026-42387?

CVE-2026-42387 has an EPSS score of 0.40% (32th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-42387?

Upgrade pdns-recursor on debian 13 to 5.2.11-0+deb13u1 or later.

CVE & CISA-KEV Catalog

CVE-2026-42387

MEDIUM

5.9

CVSS v3

NVD

Description

A malicious authoritative server can send a crafted zone via the ZoneToCache function that leads to a crash of the Recursor due to insuffcient input validation.

CWE-20Improper Input Validation

How to fix

Remediation Available

pdns-recursorDebian

Fixed in:5.2.11-0+deb13u1CVE-2026-42387

Fixed in:5.4.3-1CVE-2026-42387

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityHigh

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityHigh

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploit Intelligence

0.40%probability of exploitation in 30 days

32ndpercentile

Low risk: more likely to be exploited than 32% of all known CVEs.

References

Other references1

docs.powerdns.com

Related Vulnerabilities

Other CWE-20 (Improper Input Validation) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2024-3400	Critical	10.0	100%	KEV + Ransom	-
CVE-2021-45105	Medium	5.9	100%	-	Fix
CVE-2021-44228	Critical	10.0	100%	KEV + Ransom	Fix
CVE-2021-21985	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2018-7600	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2020-3452	High	7.5	100%	KEV	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-25.