Vulnerability · Published Apr 22, 2026 · Assigned by OX
CVE-2026-33261Null pointer accces in aggressive NSEC(3) cache
Medium 5.9
In plain English
A medium-severity security flaw in Recursor from PowerDNS. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 15% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)5.9Medium
Exploit odds (30 days)0.2%top 84.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
A zone transition from NSEC to NSEC3 might trigger an internal inconsistency and cause a denial of service.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.23 | pdns-recursor | 5.3.6-r0 | ALPINE-CVE-2026-33261 |
| Alpine:v3.24 | pdns-recursor | 5.4.1-r0 | ALPINE-CVE-2026-33261 |
| Debian:12 | pdns-recursor | no fix listed | DEBIAN-CVE-2026-33261 |
| Debian:13 | pdns-recursor | 5.2.9-0+deb13u1 | DEBIAN-CVE-2026-33261 |
| Debian:14 | pdns-recursor | 5.4.1-1 | DEBIAN-CVE-2026-33261 |
| Ubuntu:24.04:LTS | pdns-recursor | no fix listed | UBUNTU-CVE-2026-33261 |
| Ubuntu:25.10 | pdns-recursor | no fix listed | UBUNTU-CVE-2026-33261 |
| Ubuntu:26.04:LTS | pdns-recursor | no fix listed | UBUNTU-CVE-2026-33261 |
| Ubuntu:26.10 | pdns-recursor | no fix listed | UBUNTU-CVE-2026-33261 |
Affected products (as reported)
Weakness: CWE-353 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H