# CVE-2026-42389: PowerDNS Recursor insufficient validation of authoritative answers

Source: https://junglewise.ai/threats/cve-2026-42389-powerdns-recursor-insufficient-validation-of-authoritative  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-25. Updated: 2026-06-25  
License: CC BY 4.0 with a link back

CVE-2026-42389 · Severity: medium · CVSS 5.3 · Published 2026-06-25

PowerDNS Recursor, a service used to resolve internet domain names for users, contains a vulnerability in how it validates data from other servers. An attacker could potentially provide incorrect information to the system, leading to data integrity issues. This update introduces stricter validation to ensure the accuracy of the information the service provides to its users.

Technologies: [Powerdns Recursor](https://junglewise.ai/threats/technologies/recursor). Vendors: [Powerdns](https://junglewise.ai/threats/vendors/powerdns).

## Quick answers

**Is CVE-2026-42389 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-42389 being exploited in the wild.

**How severe is CVE-2026-42389?** Medium severity, with a CVSS score of 5.3, published 25 June 2026.

**Which products and versions are affected?** Powerdns Recursor 5.4.0 to 5.4.2.

**Is there a fix for CVE-2026-42389?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-42389 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-42389?** Check whether you run Powerdns Recursor at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

PowerDNS Recursor versions 5.4.0 through 5.4.2 are affected by a lack of rigorous validation for incoming DNS responses from authoritative servers. This vulnerability allows a remote, unauthenticated attacker to potentially inject or manipulate DNS data by sending crafted responses that bypass existing checks. The root cause is insufficient validation logic within the 5.4.x branch, specifically addressed in the pdns_recursor.cc component. An exploit could lead to unauthorized modification of DNS cache data. Users are advised to upgrade to version 5.4.3 or later to receive the hardening fix.

## Affected products

- PowerDNS Recursor 5.4.0 to 5.4.2

## Timeline

- 2026-06-25: disclosed
- 2026-06-25: advisory

## References

- [https://repo.powerdns.com/](https://repo.powerdns.com/)
- [https://docs.powerdns.com/recursor/security-advisories/powerdns-advisory-powerdns-2026-08.html](https://docs.powerdns.com/recursor/security-advisories/powerdns-advisory-powerdns-2026-08.html)

## Related threats

- [PowerDNS Recursor DNSSEC wildcard validation bypass in RRSIG processing](https://junglewise.ai/threats/cve-2026-52688-powerdns-recursor-dnssec-wildcard-validation-bypass-in-rrsig)
- [PowerDNS Recursor DNSSEC validation bypass in wildcard CNAME/DNAME records](https://junglewise.ai/threats/cve-2026-52686-powerdns-recursor-dnssec-validation-bypass-in-wildcard-cname)
- [PowerDNS Recursor TTL capping bypass in NS record refresh](https://junglewise.ai/threats/cve-2026-52684-powerdns-recursor-ttl-capping-bypass-in-ns-record-refresh)
- [PowerDNS Recursor DNSSEC validation failure via EDNS spoofing](https://junglewise.ai/threats/cve-2026-52690-powerdns-recursor-dnssec-validation-failure-via-edns-spoofing)
- [PowerDNS Recursor improper ZONEMD validation in ZoneToCache](https://junglewise.ai/threats/cve-2026-42390-powerdns-recursor-improper-zonemd-validation-in-zonetocache)