Vulnerability · Published Apr 22, 2026 · Assigned by OX
CVE-2026-33594Outgoing DoH excessive memory allocation
Medium 5.3
In plain English
A medium-severity resource allocation without limits in DNSdist from PowerDNS. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 31% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)5.3Medium
Exploit odds (30 days)0.4%top 68.8% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
A client can trigger excessive memory allocation by generating a lot of queries that are routed to an overloaded DoH backend, causing queries to accumulate into a buffer that will not be released until the end of the connection.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.23 | dnsdist | 2.0.4-r0 | ALPINE-CVE-2026-33594 |
| Alpine:v3.24 | dnsdist | 2.0.4-r0 | ALPINE-CVE-2026-33594 |
| Debian:12 | dnsdist | no fix listed | DEBIAN-CVE-2026-33594 |
| Debian:13 | dnsdist | 1.9.14-0+deb13u1 | DEBIAN-CVE-2026-33594 |
| Debian:14 | dnsdist | 2.0.4-1 | DEBIAN-CVE-2026-33594 |
| Ubuntu:25.10 | dnsdist | no fix listed | UBUNTU-CVE-2026-33594 |
| Ubuntu:26.04:LTS | dnsdist | no fix listed | UBUNTU-CVE-2026-33594 |
| Ubuntu:26.10 | dnsdist | no fix listed | UBUNTU-CVE-2026-33594 |
Affected products (as reported)
Weakness: CWE-770 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L