{"api_version":"1","generated_at":"2026-09-13T12:23:17+00:00","cve":"CVE-2026-19401","urls":{"html":"https://cve.report/CVE-2026-19401","api":"https://cve.report/api/cve/CVE-2026-19401.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-19401","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-19401"},"summary":{"title":"Remote UDP DoS by sending multiple DNS Cookie options","description":"Any remote client can crash a (debugging/non-release build type) NSD serve child by sending it a special crafted message with a specially tuned number of DNS Cookie options (17 when UDP payload size is 512). By continuously crashing the serve childs, the remote client can severely hamper or, when positioned sufficiently close, deny all DNS service.","state":"PUBLISHED","assigner":"NLnet Labs","published_at":"2026-08-26 09:16:45","updated_at":"2026-09-08 20:00:05"},"problem_types":["CWE-400","CWE-617","CWE-617 CWE-617 Reachable Assertion","CWE-400 CWE-400 Uncontrolled Resource Consumption"],"metrics":[{"version":"4.0","source":"sep@nlnetlabs.nl","type":"Secondary","score":"8.2","severity":"HIGH","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","data":{"version":"4.0","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","baseScore":8.2,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","confidentialityRequirement":"NOT_DEFINED","integrityRequirement":"NOT_DEFINED","availabilityRequirement":"NOT_DEFINED","modifiedAttackVector":"NOT_DEFINED","modifiedAttackComplexity":"NOT_DEFINED","modifiedAttackRequirements":"NOT_DEFINED","modifiedPrivilegesRequired":"NOT_DEFINED","modifiedUserInteraction":"NOT_DEFINED","modifiedVulnConfidentialityImpact":"NOT_DEFINED","modifiedVulnIntegrityImpact":"NOT_DEFINED","modifiedVulnAvailabilityImpact":"NOT_DEFINED","modifiedSubConfidentialityImpact":"NOT_DEFINED","modifiedSubIntegrityImpact":"NOT_DEFINED","modifiedSubAvailabilityImpact":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED"}},{"version":"4.0","source":"CNA","type":"CVSS","score":"8.2","severity":"HIGH","vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","data":{"baseScore":8.2,"baseSeverity":"HIGH","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","version":"4.0"}},{"version":"3.1","source":"nvd@nist.gov","type":"Primary","score":"7.5","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"}}],"references":[{"url":"https://www.nlnetlabs.nl/downloads/nsd/CVE-2026-19401.txt","name":"https://www.nlnetlabs.nl/downloads/nsd/CVE-2026-19401.txt","refsource":"sep@nlnetlabs.nl","tags":["Vendor Advisory"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-19401","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-19401","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"NLnet Labs","product":"NSD","version":"affected 4.3.7 4.15.1 semver","platforms":[]}],"timeline":[{"source":"CNA","time":"2026-07-15T18:04:25.000Z","lang":"en","value":"Issue reported by Qifan Zhang"},{"source":"CNA","time":"2026-08-10T07:56:32.000Z","lang":"en","value":"NLnet Labs shares patch with Qifan Zhang"},{"source":"CNA","time":"2026-08-15T00:00:00.000Z","lang":"en","value":"Qifan Zhang verifies patch"},{"source":"CNA","time":"2026-08-24T03:02:36.000Z","lang":"en","value":"Issue reported by afldl"},{"source":"CNA","time":"2026-08-24T10:10:04.000Z","lang":"en","value":"NLnet Labs shares patch with afldl"},{"source":"CNA","time":"2026-08-26T01:04:13.000Z","lang":"en","value":"afldl verifies patch"},{"source":"CNA","time":"2026-08-26T12:00:00.000Z","lang":"en","value":"Fix released with version 4.15.1"}],"solutions":[{"source":"CNA","title":"","value":"This issue is fixed in 4.15.1 and all later versions.","time":"","lang":"en"}],"workarounds":[],"exploits":[],"credits":[{"source":"CNA","value":"Qifan Zhang from Palo Alto Networks","lang":"en"},{"source":"CNA","value":"afldl <zhangph@yandex.com>","lang":"en"}],"nvd_cpes":[{"cve_year":"2026","cve_id":"19401","vulnerable":"1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"a","cpe4":"nlnetlabs","cpe5":"nsd","cpe6":"*","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"}],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"19401","cve":"CVE-2026-19401","epss":"0.003320000","percentile":"0.259880000","score_date":"2026-09-08","updated_at":"2026-09-09 00:06:18"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"adp":[{"metrics":[{"other":{"content":{"id":"CVE-2026-19401","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","timestamp":"2026-08-26T14:09:46.662987Z","version":"2.0.3"},"type":"ssvc"}}],"providerMetadata":{"dateUpdated":"2026-08-26T14:16:26.813Z","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP"},"title":"CISA ADP Vulnrichment"}],"cna":{"affected":[{"defaultStatus":"unaffected","product":"NSD","vendor":"NLnet Labs","versions":[{"lessThan":"4.15.1","status":"affected","version":"4.3.7","versionType":"semver"}]}],"credits":[{"lang":"en","type":"finder","value":"Qifan Zhang from Palo Alto Networks"},{"lang":"en","type":"finder","value":"afldl <zhangph@yandex.com>"}],"datePublic":"2026-08-26T12:00:00.000Z","descriptions":[{"lang":"en","value":"Any remote client can crash a (debugging/non-release build type) NSD serve child by sending it a special crafted message with a specially tuned number of DNS Cookie options (17 when UDP payload size is 512). By continuously crashing the serve childs, the remote client can severely hamper or, when positioned sufficiently close, deny all DNS service."}],"metrics":[{"cvssV4_0":{"baseScore":8.2,"baseSeverity":"HIGH","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","version":"4.0"},"format":"CVSS","scenarios":[{"lang":"en","value":"Remote client denying UDP availability by sending a special crafted message to a debugging build type NSD instance"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-617","description":"CWE-617 Reachable Assertion","lang":"en","type":"CWE"},{"cweId":"CWE-400","description":"CWE-400 Uncontrolled Resource Consumption","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-08-26T08:44:08.078Z","orgId":"206fc3a0-e175-490b-9eaa-a5738056c9f6","shortName":"NLnet Labs"},"references":[{"tags":["vendor-advisory"],"url":"https://www.nlnetlabs.nl/downloads/nsd/CVE-2026-19401.txt"}],"solutions":[{"lang":"en","value":"This issue is fixed in 4.15.1 and all later versions."}],"timeline":[{"lang":"en","time":"2026-07-15T18:04:25.000Z","value":"Issue reported by Qifan Zhang"},{"lang":"en","time":"2026-08-10T07:56:32.000Z","value":"NLnet Labs shares patch with Qifan Zhang"},{"lang":"en","time":"2026-08-15T00:00:00.000Z","value":"Qifan Zhang verifies patch"},{"lang":"en","time":"2026-08-24T03:02:36.000Z","value":"Issue reported by afldl"},{"lang":"en","time":"2026-08-24T10:10:04.000Z","value":"NLnet Labs shares patch with afldl"},{"lang":"en","time":"2026-08-26T01:04:13.000Z","value":"afldl verifies patch"},{"lang":"en","time":"2026-08-26T12:00:00.000Z","value":"Fix released with version 4.15.1"}],"title":"Remote UDP DoS by sending multiple DNS Cookie options","x_generator":{"engine":"cvelib 1.8.0"}}},"cveMetadata":{"assignerOrgId":"206fc3a0-e175-490b-9eaa-a5738056c9f6","assignerShortName":"NLnet Labs","cveId":"CVE-2026-19401","datePublished":"2026-08-26T08:44:08.078Z","dateReserved":"2026-08-10T07:31:26.962Z","dateUpdated":"2026-08-26T14:16:26.813Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-26 09:16:45","lastModifiedDate":"2026-09-08 20:00:05","problem_types":["CWE-400","CWE-617","CWE-617 CWE-617 Reachable Assertion","CWE-400 CWE-400 Uncontrolled Resource Consumption"],"metrics":{"cvssMetricV40":[{"source":"sep@nlnetlabs.nl","type":"Secondary","cvssData":{"version":"4.0","vectorString":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","baseScore":8.2,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"PRESENT","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","exploitMaturity":"NOT_DEFINED","confidentialityRequirement":"NOT_DEFINED","integrityRequirement":"NOT_DEFINED","availabilityRequirement":"NOT_DEFINED","modifiedAttackVector":"NOT_DEFINED","modifiedAttackComplexity":"NOT_DEFINED","modifiedAttackRequirements":"NOT_DEFINED","modifiedPrivilegesRequired":"NOT_DEFINED","modifiedUserInteraction":"NOT_DEFINED","modifiedVulnConfidentialityImpact":"NOT_DEFINED","modifiedVulnIntegrityImpact":"NOT_DEFINED","modifiedVulnAvailabilityImpact":"NOT_DEFINED","modifiedSubConfidentialityImpact":"NOT_DEFINED","modifiedSubIntegrityImpact":"NOT_DEFINED","modifiedSubAvailabilityImpact":"NOT_DEFINED","Safety":"NOT_DEFINED","Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","valueDensity":"NOT_DEFINED","vulnerabilityResponseEffort":"NOT_DEFINED","providerUrgency":"NOT_DEFINED"}}],"cvssMetricV31":[{"source":"nvd@nist.gov","type":"Primary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":3.9,"impactScore":3.6}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-08-26T14:09:46.662987Z","id":"CVE-2026-19401","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:nlnetlabs:nsd:*:*:*:*:*:*:*:*","versionStartIncluding":"4.3.7","versionEndExcluding":"4.15.1","matchCriteriaId":"6909F991-7F73-436D-B79D-ABCEC5C40989"}]}]}]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"19401","Ordinal":"1","Title":"Remote UDP DoS by sending multiple DNS Cookie options","CVE":"CVE-2026-19401","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"19401","Ordinal":"1","NoteData":"Any remote client can crash a (debugging/non-release build type) NSD serve child by sending it a special crafted message with a specially tuned number of DNS Cookie options (17 when UDP payload size is 512). By continuously crashing the serve childs, the remote client can severely hamper or, when positioned sufficiently close, deny all DNS service.","Type":"Description","Title":"Remote UDP DoS by sending multiple DNS Cookie options"}]}}}