{"id":"CVE-2026-40209","state":"PUBLISHED","title":"Denial of service via IXFR queries","description":"An attacker might be able to cause outgoing TCP connections to backend to be stuck until a timeout occurs instead of being released immediately, by sending IXFR queries. This could be used to cause a denial of service if there is a limit to the number of concurrent connections to this backend, or if the process runs out of file descriptors.","publishedAt":"2026-06-25T12:23:05.694Z","updatedAt":"2026-06-25T13:56:22.793Z","severity":{"score":5.3,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","source":"OX"},"assigner":"OX","products":["PowerDNS DNSdist"],"affected":[{"vendor":"PowerDNS","product":"DNSdist","packageName":"dnsdist","defaultStatus":"unaffected","versions":[{"version":"1.9.0","status":"affected","lessThan":"1.9.15","versionType":"semver"},{"version":"2.0.0","status":"affected","lessThan":"2.0.7","versionType":"semver"}],"collectionURL":"https://repo.powerdns.com/","repo":"https://github.com/PowerDNS/pdns","modules":["DNS over TCP to the backend"],"programFiles":["dnsdist-tcp-downstream.cc"]}],"references":["https://www.dnsdist.org/security-advisories/powerdns-advisory-for-dnsdist-2026-09.html"],"weaknesses":["CWE-772"],"ingestedAt":"2026-10-29T20:11:57.932Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/40xxx/CVE-2026-40209.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-40209","state":"PUBLISHED","datePublished":"2026-06-25T12:23:05.694Z","dateUpdated":"2026-06-25T13:56:22.793Z","assignerShortName":"OX","assignerOrgId":"8ce71d90-2354-404b-a86e-bec2cc4e6981","dateReserved":"2026-04-10T07:11:39.060Z"},"containers":{"cna":{"title":"Denial of service via IXFR queries","descriptions":[{"lang":"en","value":"An attacker might be able to cause outgoing TCP connections to backend to be stuck until a timeout occurs instead of being released immediately, by sending IXFR queries. This could be used to cause a denial of service if there is a limit to the number of concurrent connections to this backend, or if the process runs out of file descriptors."}],"affected":[{"vendor":"PowerDNS","product":"DNSdist","packageName":"dnsdist","defaultStatus":"unaffected","versions":[{"version":"1.9.0","status":"affected","lessThan":"1.9.15","versionType":"semver"},{"version":"2.0.0","status":"affected","lessThan":"2.0.7","versionType":"semver"}],"collectionURL":"https://repo.powerdns.com/","repo":"https://github.com/PowerDNS/pdns","modules":["DNS over TCP to the backend"],"programFiles":["dnsdist-tcp-downstream.cc"]}],"references":[{"url":"https://www.dnsdist.org/security-advisories/powerdns-advisory-for-dnsdist-2026-09.html"}],"metrics":[{"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}],"cvssV3_1":{"version":"3.1","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"LOW","baseSeverity":"MEDIUM","baseScore":5.3,"vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"}}],"problemTypes":[{"descriptions":[{"lang":"en","description":"Missing Release of Resource after Effective Lifetime","type":"CWE"}]}],"providerMetadata":{"shortName":"OX","orgId":"8ce71d90-2354-404b-a86e-bec2cc4e6981","dateUpdated":"2026-06-25T12:23:05.694Z"},"datePublic":"2026-06-24T22:00:00.000Z","credits":[{"lang":"en","value":"Qifan Zhang (Palo Alto Networks)","type":"finder"}],"source":{"discovery":"UNKNOWN"},"x_generator":{"engine":"Vulnogram 1.0.2"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-06-25T13:56:17.791790Z","id":"CVE-2026-40209","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-772","type":"CWE","lang":"en","description":"CWE-772 Missing Release of Resource after Effective Lifetime"}]}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-06-25T13:56:22.793Z"}}]}}}