Vulnerability · Published Jun 25, 2026 · Assigned by OX
CVE-2026-40012Information about ECS zero scoped answers might leak to clients that use a specific ECS
Medium 5.3
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 0.5% (higher than 39% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 3.1)5.3Medium
Exploit odds (30 days)0.5%top 60.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
ECS zero scoped answers are stored in the packet cache while they should not. This impacts only configurations that have ECS enabled;
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.24 | pdns-recursor | 5.4.3-r0 | ALPINE-CVE-2026-40012 |
| Debian:12 | pdns-recursor | no fix listed | DEBIAN-CVE-2026-40012 |
| Debian:13 | pdns-recursor | 5.2.11-0+deb13u1 | DEBIAN-CVE-2026-40012 |
| Debian:14 | pdns-recursor | 5.4.3-1 | DEBIAN-CVE-2026-40012 |
| Ubuntu:24.04:LTS | pdns-recursor | no fix listed | UBUNTU-CVE-2026-40012 |
| Ubuntu:25.10 | pdns-recursor | no fix listed | UBUNTU-CVE-2026-40012 |
| Ubuntu:26.04:LTS | pdns-recursor | no fix listed | UBUNTU-CVE-2026-40012 |
| Ubuntu:26.10 | pdns-recursor | no fix listed | UBUNTU-CVE-2026-40012 |
Affected products (as reported)
Weakness: CWE-524 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N