CVE-2026-33601 Insufficient validation of zonemd record
An attacker can cause a denial of service in PowerDNS Recursor by sending a malicious zone from an authoritative server, triggering a null pointer dereference.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-33601?
CVE-2026-33601 is a medium-severity vulnerability in Powerdns Recursor, published on 22 Apr 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Official description
If you use the zoneToCache function with a malicious authoritative server, an attacker can send a zone that result in a null pointer dereference, caused by a missing consistency check and leading to a denial of service.
Weakness: CWE-476
Which versions are affected by CVE-2026-33601?
It affects 1 product.
Products include Powerdns Recursor.
How do I fix CVE-2026-33601?
Apply the vendor's patch.
Is CVE-2026-33601 being exploited?
There is no known exploitation of CVE-2026-33601 in the wild and no public exploit code.
Other vulnerabilities in Powerdns Recursor
- CVE-2009-4009 Memory corruption in n/a
- CVE-2020-10030 Memory corruption in n/a
- CVE-2025-59023 Crafted delegations or IP fragments can poison cached delegations in Recursor
- CVE-2025-59030 Insufficient validation of incoming notifies over TCP can lead to a denial of service in Recursor
- CVE-2023-22617 Denial of service in n/a
Sources
Also known as DEBIAN-CVE-2026-33601, GHSA-5h99-7732-g93r, UBUNTU-CVE-2026-33601.