{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-86250","assignerOrgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","state":"PUBLISHED","assignerShortName":"VulnCheck","dateReserved":"2026-09-06T11:35:19.316Z","datePublished":"2026-09-06T12:00:26.211Z","dateUpdated":"2026-09-18T17:23:10.520Z"},"containers":{"cna":{"providerMetadata":{"orgId":"83251b91-4cc7-4094-a5c7-464a1b83ea10","shortName":"VulnCheck","dateUpdated":"2026-09-06T12:00:26.211Z"},"datePublic":"2026-03-21T00:00:00.000Z","title":"h3 before 2.0.1-rc.18 Denial of Service via Unbounded Chunked Cookie","descriptions":[{"lang":"en","value":"h3 versions before 2.0.1-rc.18 fail to validate the chunk count parsed from user-controlled cookie values in setChunkedCookie() and deleteChunkedCookie() functions. Attackers can send a crafted cookie header with an extremely large chunk count to trigger an O(n²) cleanup loop that hangs the server process."}],"problemTypes":[{"descriptions":[{"lang":"en","description":"Uncontrolled Resource Consumption","cweId":"CWE-400","type":"CWE"}]}],"affected":[{"vendor":"h3js","product":"h3","defaultStatus":"unaffected","packageURL":"pkg:npm/h3","versions":[{"version":"2.0.0-beta.4","status":"affected","versionType":"semver","lessThan":"2.0.1-rc.18"},{"version":"2.0.1-rc.18","status":"unaffected","versionType":"semver"}]}],"metrics":[{"format":"CVSS","cvssV4_0":{"version":"4.0","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","attackVector":"NETWORK","attackComplexity":"LOW","attackRequirements":"NONE","privilegesRequired":"NONE","userInteraction":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE","vulnAvailabilityImpact":"HIGH","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","subAvailabilityImpact":"NONE","baseScore":8.7,"baseSeverity":"HIGH"}},{"format":"CVSS","cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH","baseScore":7.5,"baseSeverity":"HIGH"}}],"references":[{"url":"https://github.com/h3js/h3/security/advisories/GHSA-q5pr-72pq-83v3","tags":["vendor-advisory"],"name":"GitHub Security Advisory (GHSA-q5pr-72pq-83v3)"},{"name":"VulnCheck Advisory: h3 before 2.0.1-rc.18 Denial of Service via Unbounded Chunked Cookie","tags":["third-party-advisory"],"url":"https://www.vulncheck.com/advisories/h3-before-2.0.1-rc.18-denial-of-service-via-unbounded-chunked-cookie"}],"credits":[{"lang":"en","value":"offset","type":"reporter"}],"x_generator":{"engine":"vulncheck-endgame"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-86250","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2026-09-18T17:07:52.002310Z"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-09-18T17:23:10.520Z"}}]}}