Input validation error in PowerDNS Recursor - CVE-2026-42387
Published: June 25, 2026
Vulnerability identifier: #VU135386
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-42387
CWE-ID: CWE-20
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: PowerDNS.COM B.V.
Affected software:
PowerDNS Recursor
PowerDNS Recursor
Detailed vulnerability description
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to improper input validation in the ZoneToCache function when processing a crafted zone containing an invalid RRSIG record. A remote attacker can send a crafted zone to cause a denial of service.
Only configurations that use ZoneToCache are vulnerable.
How to mitigate CVE-2026-42387
Install security update from vendor's website.