PatchSiren cyber security CVE debrief
CVE-2026-42000 PowerDNS CVE debrief
CVE-2026-42000 is a medium-severity DNS vulnerability described as insufficient validation of names during AXFR, the zone-transfer process used by authoritative DNS servers. The available corpus points to a PowerDNS security advisory, but the vendor mapping in the source data is still low-confidence and should be treated as provisional.
- Vendor
- PowerDNS
- Product
- Authoritative
- CVSS
- MEDIUM 6.8
- CISA KEV
- Not listed in stored evidence
- Original CVE published
- 2026-05-21
- Original CVE updated
- 2026-05-21
- Advisory published
- 2026-05-21
- Advisory updated
- 2026-05-21
Who should care
Operators and administrators of authoritative DNS infrastructure, especially environments that expose AXFR to secondary servers or other trusted peers, should review this issue and compare their deployments against the referenced PowerDNS advisory.
Technical summary
The source data describes a validation weakness during AXFR, with NVD assigning CVSS 3.1 vector AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N (6.8). That combination suggests a network-reachable issue that may require specific conditions, and whose primary risk is integrity impact rather than confidentiality or availability. The corpus does not include the advisory body itself, so affected versions, exact failure mode, and remediation details should be confirmed in the linked vendor notice.
Defensive priority
Medium. Confirm whether your authoritative DNS deployment is affected, then prioritize vendor guidance and patching because the issue can affect integrity through network-accessible AXFR handling.
Recommended defensive actions
- Open and review the linked PowerDNS advisory to confirm affected products and versions.
- Apply the vendor-recommended update or mitigation as soon as it is validated for your environment.
- Restrict AXFR to explicitly trusted secondary DNS servers and verify access-control settings.
- Audit authoritative DNS configurations for unintended zone-transfer exposure.
- Monitor DNS logs for unusual AXFR activity or unexpected transfer requests.
- Test changes in a staging environment before rollout to avoid disrupting name resolution.
Evidence notes
Evidence in the supplied corpus is limited to the NVD record, which cites a PowerDNS security advisory as the reference source. The title and CVSS vector support a network-reachable DNS integrity issue, but the corpus does not include the advisory text, affected versions, or a confirmed product mapping. Vendor attribution is therefore provisional.
Official resources
-
CVE-2026-42000 CVE record
CVE.org
-
CVE-2026-42000 NVD detail
NVD
-
Source item URL
nvd_modified
- Source reference
CVE-2026-42000 was published and last modified on 2026-05-21T10:16:25.563Z in the supplied timeline. The issue is not listed in CISA KEV in the provided enrichment data.