Description
An attacker spoofing answers to ECS enabled requests sent out by the Recursor has a chance of success higher than non-ECS enabled queries.
The updated version include various mitigations against spoofing attempts of ECS enabled queries by chaining ECS enabled requests and enforcing stricter validation of the received answers.
The most strict mitigation done when the new setting outgoing.edns_subnet_harden (old style name edns-subnet-harden) is enabled.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| PowerDNS | Recursor | — | 5.0.12 |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | pdns-recursor | 5.2.4-2 | — |
| Debian 13 | pdns-recursor | 5.2.4-2 | — |
| Debian 12 | pdns-recursor | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | pdns-recursor | No fix yet | — |
| Ubuntu 26.04 LTS | pdns-recursor | No fix yet | — |
| Ubuntu 25.10 | pdns-recursor | No fix yet | — |
| Ubuntu 24.04 LTS | pdns-recursor | No fix yet | — |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 22.04 LTS | pdns-recursor | No fix yet | — |
| Ubuntu Pro 20.04 LTS | pdns-recursor | No fix yet | — |
| Ubuntu Pro 18.04 LTS | pdns-recursor | No fix yet | — |
| Ubuntu Pro 16.04 LTS | pdns-recursor | No fix yet | — |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | pdns-recursor | 5.2.5-1.1 | openSUSE-SU-2025:15478-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | pdns-recursor | 5.2.5-r0 | — |
| Alpine v3.23 | pdns-recursor | 5.2.5-r0 | — |
| Alpine v3.22 | pdns-recursor | 5.2.2-r0 | — |
Advisories 2
- openSUSE-SU-2025:15478-1 pdns-recursor-5.2.5-1.1 on GA media SUSE / openSUSE Security Updates · Mar 23, 2026
- WID-SEC-2025-1614 PowerDNS: Schwachstelle ermöglicht Denial of Service BSI CERT-Bund (WID) · Aug 24, 2025