Cache Management Flaw in PowerDNS Recursor Affects ECS Configurations
CVE-2026-40012

5.3MEDIUM

Key Information:

Vendor

Powerdns

Status
Recursor
Vendor
CVE Published:
25 June 2026

What is CVE-2026-40012?

A configuration oversight in PowerDNS Recursor leads to zero scoped answers being improperly stored in the packet cache when ECS (EDNS Client Subnet) is enabled. This issue may expose sensitive network information and create potential security risks for users relying on ECS configurations.

Affected Version(s)

Recursor 5.2.0 < 5.2.11

Recursor 5.3.0 < 5.3.8

Recursor 5.4.0 < 5.4.3

References

https://docs.powerdns.com/recursor/security-advisories/po...

CVSS V3.1

Score:
5.3
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
None
Availability:
Low
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Danial Mahadzir
.