Quick answers
- Is CVE-2026-42396 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-42396 being exploited in the wild.
- How severe is CVE-2026-42396?
- Medium severity, with a CVSS score of 4.9, published 21 May 2026.
- Which products and versions are affected?
- PowerDNS Authoritative Server.
- Is there a fix for CVE-2026-42396?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-42396 attacked?
- It is attacked over the network, in a hosted service.
- Am I affected by CVE-2026-42396?
- Check whether you run Powerdns Authoritative Server. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
PowerDNS Authoritative Server is vulnerable to a denial of service condition during catalog zone transfers. The root cause is insufficient validation of member zone data within the catalog zone. An attacker with high privileges (sufficient to modify or inject data into a catalog zone) can provide malformed or unexpected member zone data that causes the transfer process to fail. This prevents the synchronization of DNS zones across the infrastructure. The vulnerability is tracked as CVE-2026-42396 and was reported by Open-Xchange.
Affected products
- PowerDNS Authoritative Server
Timeline
- 2026-05-21: disclosed: Initial advisory publication