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PatchSiren cyber security CVE debrief

CVE-2026-40208 PowerDNS CVE debrief

An attacker might be able to delay the processing of DoH3 queries by sending DoH3 GET queries with an invalid DATA frame. This issue affects Dnsdist. The CVE record was published on 2026-06-25T13:16:39.427Z and has not been modified since then. The NVD entry is currently Deferred. This vulnerability could potentially impact DNS infrastructure, particularly for those using Dnsdist, by causing delays in query processing. Defenders should assess their exposure and verify affected versions to understand the potential operational impact.

Vendor
PowerDNS
Product
DNSdist
CVSS
LOW 3.7
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-25
Original CVE updated
2026-10-25
Advisory published
2026-06-25
Advisory updated
2026-10-25

Who should care

Defenders responsible for DNS infrastructure, particularly those using Dnsdist, should assess exposure and verify affected versions. This includes operators of DNS services, security teams, and vulnerability management teams who need to understand the potential impact on their systems and take appropriate actions to mitigate the vulnerability.

Why it matters

CVE-2026-40208 is a low-severity vulnerability in Dnsdist that allows an attacker to delay DoH3 query processing. Defenders should verify affected versions, assess exposure, and monitor for potential delays.

  • Potential delays in DoH3 query processing
  • Need to verify affected versions of Dnsdist
  • Assess exposure in DNS infrastructure
  • Monitor for potential delays in DoH3 query processing

Technical summary

CVE-2026-40208 is a vulnerability in Dnsdist that allows an attacker to delay the processing of DoH3 queries by sending DoH3 GET queries with an invalid DATA frame. The CVSS score is 3.7, indicating a low severity vulnerability. This issue could affect DNS infrastructure that relies on Dnsdist, and defenders should verify affected versions and assess their exposure to this vulnerability.

Defensive priority

Defenders should prioritize verifying affected versions and assessing exposure in their DNS infrastructure.

Recommended defensive actions

  • Verify affected versions of Dnsdist in use
  • Assess exposure in DNS infrastructure
  • Monitor for potential delays in DoH3 query processing

Evidence notes

The CVE record and NVD entry provide limited information about the vulnerability. Further verification is required to determine affected versions and potential impact.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-40208 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-40208

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

  • CVE-2026-40208 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-40208

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

Supplemental references

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.