{"api_version":"1","generated_at":"2026-07-07T18:15:56+00:00","cve":"CVE-2026-9545","urls":{"html":"https://cve.report/CVE-2026-9545","api":"https://cve.report/api/cve/CVE-2026-9545.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-9545","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-9545"},"summary":{"title":"exposing HTTP/3 early data","description":"In this scenario, libcurl first uses a proper HTTP/3 server for the initial\ntransfers, and when it makes a second transfer to the same site it has been\nreplaced by the attacker's impostor machine - without a valid certificate.\n\nWhen libcurl returns to the hostname the second time with a cached SSL session\n(`CURLOPT_SSL_SESSIONID_CACHE` is not disabled) and early data enabled (the\n`CURLSSLOPT_EARLYDATA` bit is set in `CURLOPT_SSL_OPTIONS`), libcurl might\nsend off the second request's bytes on that new connection *before* enforcing\nthe certificate verification failure. Potentially leaking sensitive\ninformation.","state":"PUBLISHED","assigner":"curl","published_at":"2026-07-03 07:16:25","updated_at":"2026-07-07 15:03:56"},"problem_types":["NVD-CWE-noinfo","CWE-200 Exposure of Sensitive Information to an Unauthorized Actor"],"metrics":[{"version":"3.1","source":"ADP","type":"DECLARED","score":"7.5","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","data":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","version":"3.1"}},{"version":"3.1","source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","type":"Secondary","score":"7.5","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","baseScore":7.5,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"NONE","availabilityImpact":"NONE"}}],"references":[{"url":"https://curl.se/docs/CVE-2026-9545.html","name":"https://curl.se/docs/CVE-2026-9545.html","refsource":"2499f714-1537-4658-8207-48ae4bb9eae9","tags":["Patch","Vendor Advisory"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://curl.se/docs/CVE-2026-9545.json","name":"https://curl.se/docs/CVE-2026-9545.json","refsource":"2499f714-1537-4658-8207-48ae4bb9eae9","tags":["Vendor Advisory"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://hackerone.com/reports/3752888","name":"https://hackerone.com/reports/3752888","refsource":"134c704f-9b21-4f2e-91b3-4a467353bcc0","tags":["Exploit","Issue Tracking","Third Party Advisory"],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-9545","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-9545","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"curl","product":"curl","version":"affected 8.20.0 8.20.0 semver","platforms":[]},{"source":"CNA","vendor":"curl","product":"curl","version":"affected 8.19.0 8.19.0 semver","platforms":[]},{"source":"CNA","vendor":"curl","product":"curl","version":"affected 8.18.0 8.18.0 semver","platforms":[]},{"source":"CNA","vendor":"curl","product":"curl","version":"affected 8.17.0 8.17.0 semver","platforms":[]},{"source":"CNA","vendor":"curl","product":"curl","version":"affected 8.16.0 8.16.0 semver","platforms":[]},{"source":"CNA","vendor":"curl","product":"curl","version":"affected 8.15.0 8.15.0 semver","platforms":[]},{"source":"CNA","vendor":"curl","product":"curl","version":"affected 8.14.1 8.14.1 semver","platforms":[]},{"source":"CNA","vendor":"curl","product":"curl","version":"affected 8.14.0 8.14.0 semver","platforms":[]},{"source":"CNA","vendor":"curl","product":"curl","version":"affected 8.13.0 8.13.0 semver","platforms":[]},{"source":"CNA","vendor":"curl","product":"curl","version":"affected 8.12.1 8.12.1 semver","platforms":[]},{"source":"CNA","vendor":"curl","product":"curl","version":"affected 8.12.0 8.12.0 semver","platforms":[]},{"source":"CNA","vendor":"curl","product":"curl","version":"affected 8.11.1 8.11.1 semver","platforms":[]},{"source":"CNA","vendor":"curl","product":"curl","version":"affected 8.11.0 8.11.0 semver","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[{"source":"CNA","value":"Eunsoo Kim (Autonomous Code Security team at Microsoft)","lang":"en"},{"source":"CNA","value":"Stefan Eissing","lang":"en"}],"nvd_cpes":[{"cve_year":"2026","cve_id":"9545","vulnerable":"1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"a","cpe4":"haxx","cpe5":"curl","cpe6":"*","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"}],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"9545","cve":"CVE-2026-9545","epss":"0.001340000","percentile":"0.032110000","score_date":"2026-07-06","updated_at":"2026-07-07 00:05:10"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"adp":[{"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"HIGH","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","version":"3.1"}},{"other":{"content":{"id":"CVE-2026-9545","options":[{"Exploitation":"poc"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","timestamp":"2026-07-06T16:52:42.898546Z","version":"2.0.3"},"type":"ssvc"}}],"providerMetadata":{"dateUpdated":"2026-07-06T16:53:23.396Z","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP"},"references":[{"tags":["exploit"],"url":"https://hackerone.com/reports/3752888"}],"title":"CISA ADP Vulnrichment"}],"cna":{"affected":[{"defaultStatus":"unaffected","product":"curl","vendor":"curl","versions":[{"lessThanOrEqual":"8.20.0","status":"affected","version":"8.20.0","versionType":"semver"},{"lessThanOrEqual":"8.19.0","status":"affected","version":"8.19.0","versionType":"semver"},{"lessThanOrEqual":"8.18.0","status":"affected","version":"8.18.0","versionType":"semver"},{"lessThanOrEqual":"8.17.0","status":"affected","version":"8.17.0","versionType":"semver"},{"lessThanOrEqual":"8.16.0","status":"affected","version":"8.16.0","versionType":"semver"},{"lessThanOrEqual":"8.15.0","status":"affected","version":"8.15.0","versionType":"semver"},{"lessThanOrEqual":"8.14.1","status":"affected","version":"8.14.1","versionType":"semver"},{"lessThanOrEqual":"8.14.0","status":"affected","version":"8.14.0","versionType":"semver"},{"lessThanOrEqual":"8.13.0","status":"affected","version":"8.13.0","versionType":"semver"},{"lessThanOrEqual":"8.12.1","status":"affected","version":"8.12.1","versionType":"semver"},{"lessThanOrEqual":"8.12.0","status":"affected","version":"8.12.0","versionType":"semver"},{"lessThanOrEqual":"8.11.1","status":"affected","version":"8.11.1","versionType":"semver"},{"lessThanOrEqual":"8.11.0","status":"affected","version":"8.11.0","versionType":"semver"}]}],"credits":[{"lang":"en","type":"finder","value":"Eunsoo Kim (Autonomous Code Security team at Microsoft)"},{"lang":"en","type":"remediation developer","value":"Stefan Eissing"}],"descriptions":[{"lang":"en","value":"In this scenario, libcurl first uses a proper HTTP/3 server for the initial\ntransfers, and when it makes a second transfer to the same site it has been\nreplaced by the attacker's impostor machine - without a valid certificate.\n\nWhen libcurl returns to the hostname the second time with a cached SSL session\n(`CURLOPT_SSL_SESSIONID_CACHE` is not disabled) and early data enabled (the\n`CURLSSLOPT_EARLYDATA` bit is set in `CURLOPT_SSL_OPTIONS`), libcurl might\nsend off the second request's bytes on that new connection *before* enforcing\nthe certificate verification failure. Potentially leaking sensitive\ninformation."}],"problemTypes":[{"descriptions":[{"description":"CWE-200 Exposure of Sensitive Information to an Unauthorized Actor","lang":"en"}]}],"providerMetadata":{"dateUpdated":"2026-07-03T06:17:55.931Z","orgId":"2499f714-1537-4658-8207-48ae4bb9eae9","shortName":"curl"},"references":[{"name":"json","url":"https://curl.se/docs/CVE-2026-9545.json"},{"name":"www","url":"https://curl.se/docs/CVE-2026-9545.html"},{"name":"issue","url":"https://hackerone.com/reports/3752888"}],"title":"exposing HTTP/3 early data"}},"cveMetadata":{"assignerOrgId":"2499f714-1537-4658-8207-48ae4bb9eae9","assignerShortName":"curl","cveId":"CVE-2026-9545","datePublished":"2026-07-03T06:17:55.931Z","dateReserved":"2026-05-26T06:45:08.680Z","dateUpdated":"2026-07-06T16:53:23.396Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-07-03 07:16:25","lastModifiedDate":"2026-07-07 15:03:56","problem_types":["NVD-CWE-noinfo","CWE-200 Exposure of Sensitive Information to an Unauthorized Actor"],"metrics":{"cvssMetricV31":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","baseScore":7.5,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"NONE","availabilityImpact":"NONE"},"exploitabilityScore":3.9,"impactScore":3.6}],"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-07-06T16:52:42.898546Z","id":"CVE-2026-9545","options":[{"exploitation":"poc"},{"automatable":"yes"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:*","versionStartIncluding":"8.11.0","versionEndExcluding":"8.21.0","matchCriteriaId":"C6D1007D-3E09-4D44-993A-9ACC2316FD0A"}]}]}]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"9545","Ordinal":"1","Title":"exposing HTTP/3 early data","CVE":"CVE-2026-9545","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"9545","Ordinal":"1","NoteData":"In this scenario, libcurl first uses a proper HTTP/3 server for the initial\ntransfers, and when it makes a second transfer to the same site it has been\nreplaced by the attacker's impostor machine - without a valid certificate.\n\nWhen libcurl returns to the hostname the second time with a cached SSL session\n(`CURLOPT_SSL_SESSIONID_CACHE` is not disabled) and early data enabled (the\n`CURLSSLOPT_EARLYDATA` bit is set in `CURLOPT_SSL_OPTIONS`), libcurl might\nsend off the second request's bytes on that new connection *before* enforcing\nthe certificate verification failure. Potentially leaking sensitive\ninformation.","Type":"Description","Title":"exposing HTTP/3 early data"}]}}}