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PatchSiren cyber security CVE debrief

CVE-2026-33259 Powerdns CVE debrief

A vulnerability in PowerDNS Recursor could lead to inconsistent RPZ data, use after free, and/or a crash when many concurrent transfers of the same RPZ occur. This situation typically requires a malfunctioning RPZ provider. The vulnerability affects PowerDNS Recursor deployments, which are commonly used in network infrastructure. Network administrators and security teams should assess exposure and prioritize updates to mitigate potential crashes and data inconsistencies. Evidence is limited, and further verification is needed to determine actual exploitation and impact.

Vendor
Powerdns
Product
Recursor
CVSS
MEDIUM 5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-04-22
Original CVE updated
2026-10-26
Advisory published
2026-04-22
Advisory updated
2026-10-26

Who should care

Network administrators and security teams responsible for PowerDNS Recursor deployments should assess exposure and prioritize updates to mitigate potential crashes and data inconsistencies.

Why it matters

Defenders should care about CVE-2026-33259 because it can lead to crashes and data inconsistencies in PowerDNS Recursor deployments. Network administrators and security teams should verify and update PowerDNS Recursor to mitigate these risks. The vulnerability typically requires a malfunctioning RPZ provider to be exploited. Evidence is limited, and further verification is needed to determine actual exploitation and impact.

  • Potential crashes of the PowerDNS Recursor
  • Inconsistent RPZ data due to concurrent transfers
  • Use after free vulnerabilities
  • Verification of PowerDNS Recursor versions and configurations

Technical summary

The vulnerability occurs when many concurrent transfers of the same RPZ zone happen, which can lead to inconsistent RPZ data, use after free, and/or a crash of the recursor. This situation typically requires a malfunctioning RPZ provider. The affected product is PowerDNS Recursor, and the vulnerability has a CVSS score of 5, indicating a medium severity level. The CVE record and NVD entry provide details on the vulnerability, including its CVSS score and affected versions.

Defensive priority

Defenders should prioritize verifying and updating PowerDNS Recursor to mitigate potential crashes and data inconsistencies. This requires immediate attention from network administrators and security teams.

Recommended defensive actions

  • Verify and update PowerDNS Recursor to the latest version
  • Monitor for concurrent transfers of the same RPZ zone
  • Review and adjust RPZ provider configurations

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, including its CVSS score and affected versions. However, information on actual exploitation and impact is limited.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-33259 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-33259

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-33259 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-33259

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • Source reference

    Unverified legacy reference

    URL: https://docs.powerdns.com/recursor/security-advisories/powerdns-advisory-powerdns-2026-03.html

    [email protected] - Broken Link, Vendor Advisory

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.