CVE-2026-33258 Crafted zones can cause increased resource usage
An attacker can cause resource exhaustion and denial of service in PowerDNS Recursor by publishing and querying crafted DNS zones.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-33258?
CVE-2026-33258 is a medium-severity denial of service vulnerability in Powerdns Recursor, published on 22 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
By publishing and querying a crafted zone an attacker can cause allocation of large entries in the negative and aggressive NSEC(3) caches.
Weakness: CWE-770
Which versions are affected by CVE-2026-33258?
It affects 1 product.
Products include Powerdns Recursor.
How do I fix CVE-2026-33258?
Upgrade to a fixed version.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-33258 being exploited?
There is no known exploitation of CVE-2026-33258 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-2026-33258, GHSA-mfmv-pg93-65w5, UBUNTU-CVE-2026-33258.