CVE-2026-0398 Crafted zones can lead to increased resource usage and crafted CNAME chains can lead to cache poisoning in Recursor
Attackers can cause resource exhaustion or cache poisoning in PowerDNS Recursor via crafted zones and CNAME chains.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-0398?
CVE-2026-0398 is a medium-severity denial of service vulnerability in Powerdns Recursor, published on 9 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Crafted zones can lead to increased resource usage and crafted CNAME chains can lead to cache poisoning in Recursor.
Weakness: CWE-770
Which versions are affected by CVE-2026-0398?
It affects 1 product.
Products include Powerdns Recursor.
How do I fix CVE-2026-0398?
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-2026-0398 being exploited?
There is no known exploitation of CVE-2026-0398 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-2026-0398, GHSA-6253-fq97-5xpm, UBUNTU-CVE-2026-0398.