Insufficient input validation in ZoneToCache

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.

Scores

EPSS (exploitation in 30 days)

0.48% · top 58% of all CVEs (6 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.9.

Weakness

• Improper Input Validation
• CWE-20 Improper Input Validation (opens in a new tab)All about CWE-20 and its CVEs

Affected products

• PowerDNS · Recursor

  • affected 5.2.0 – < 5.2.11
  • affected 5.3.0 – < 5.3.8
  • affected 5.4.0 – < 5.4.3

References (1)

• https://docs.powerdns.com/recursor/security-advisories/powerdns-advisory-powerdns-2026-08.html (opens in a new tab)

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2026-42387](https://trackcve.app/badge/CVE-2026-42387.svg)](https://trackcve.app/cve/CVE-2026-42387)

Record last updated 25 Jun 2026, 14:41 UTC.