What’s Vulnerable › Vulnerabilities
CVE-2026-40012: Information about ECS zero scoped answers might leak to clients that use a specific ECS
- Severity: medium (CVSS 5.3 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.5% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2026-06-25 · updated 2026-10-25
- Weakness: CWE-524
Description
ECS zero scoped answers are stored in the packet cache while they should not. This impacts only configurations that have ECS enabled;
Affected products
- PowerDNS Recursor: from 5.2.0 before 5.2.11; from 5.3.0 before 5.3.8; from 5.4.0 before 5.4.3 — fixed in 5.2.11, 5.3.8, 5.4.3
How to fix
Upgrade to a fixed version: PowerDNS Recursor 5.2.11, 5.3.8, 5.4.3. Check the vendor advisory for mitigations.
References
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