{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-9545", "assignerOrgId": "2499f714-1537-4658-8207-48ae4bb9eae9", "state": "PUBLISHED", "assignerShortName": "curl", "dateReserved": "2026-05-26T06:45:08.680Z", "datePublished": "2026-07-03T06:17:55.931Z", "dateUpdated": "2026-09-15T06:03:31.804Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "2499f714-1537-4658-8207-48ae4bb9eae9", "shortName": "curl", "dateUpdated": "2026-09-15T06:03:31.804Z" }, "title": "exposing HTTP/3 early data", "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." } ], "affected": [ { "vendor": "curl", "product": "curl", "versions": [ { "version": "8.11.0", "status": "affected", "versionType": "semver", "lessThan": "8.14.2" }, { "version": "8.15.0", "status": "affected", "versionType": "semver", "lessThan": "8.16.1" }, { "version": "8.17.0", "status": "affected", "versionType": "semver", "lessThan": "8.20.1" } ], "defaultStatus": "unaffected" }, { "vendor": "curl", "product": "curl", "versions": [ { "version": "962097b8dd44ed5b9e7984bc1cdffdbdd566857f", "status": "affected", "versionType": "git", "lessThan": "7b9613fa9b1a5e04301a3920eef58e8138dad05e" } ], "defaultStatus": "unaffected", "repo": "https://github.com/curl/curl.git" }, { "vendor": "curl", "product": "curl", "versions": [ { "version": "8.20.0", "status": "affected" }, { "version": "8.19.0", "status": "affected" }, { "version": "8.18.0", "status": "affected" }, { "version": "8.17.0", "status": "affected" }, { "version": "8.16.0", "status": "affected" }, { "version": "8.15.0", "status": "affected" }, { "version": "8.14.1", "status": "affected" }, { "version": "8.14.0", "status": "affected" }, { "version": "8.13.0", "status": "affected" }, { "version": "8.12.1", "status": "affected" }, { "version": "8.12.0", "status": "affected" }, { "version": "8.11.1", "status": "affected" }, { "version": "8.11.0", "status": "affected" } ], "defaultStatus": "unaffected" } ], "references": [ { "url": "https://curl.se/docs/CVE-2026-9545.json" }, { "url": "https://curl.se/docs/CVE-2026-9545.html" }, { "url": "https://hackerone.com/reports/3752888" } ], "x_osv": { "schema_version": "1.5.0", "id": "CURL-CVE-2026-9545", "aliases": [ "CVE-2026-9545" ], "summary": "exposing HTTP/3 early data", "modified": "2026-09-07T10:34:51.00Z", "database_specific": { "package": "curl", "affects": "both", "URL": "https://curl.se/docs/CVE-2026-9545.json", "www": "https://curl.se/docs/CVE-2026-9545.html", "issue": "https://hackerone.com/reports/3752888", "CWE": { "id": "CWE-200", "desc": "Exposure of Sensitive Information to an Unauthorized Actor" }, "last_affected": "8.20.0", "severity": "Low" }, "published": "2026-06-24T08:00:00.00Z", "affected": [ { "ranges": [ { "type": "SEMVER", "events": [ { "introduced": "8.11.0" }, { "fixed": "8.14.2" }, { "introduced": "8.15.0" }, { "fixed": "8.16.1" }, { "introduced": "8.17.0" }, { "fixed": "8.20.1" } ] }, { "type": "GIT", "repo": "https://github.com/curl/curl.git", "events": [ { "introduced": "962097b8dd44ed5b9e7984bc1cdffdbdd566857f" }, { "fixed": "7b9613fa9b1a5e04301a3920eef58e8138dad05e" } ] } ], "versions": [ "8.20.0", "8.19.0", "8.18.0", "8.17.0", "8.16.0", "8.15.0", "8.14.1", "8.14.0", "8.13.0", "8.12.1", "8.12.0", "8.11.1", "8.11.0" ] } ], "credits": [ { "name": "Eunsoo Kim (Autonomous Code Security team at Microsoft)", "type": "finder" }, { "name": "Stefan Eissing", "type": "remediation developer" } ], "details": "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": [ { "lang": "en", "description": "Exposure of Sensitive Information to an Unauthorized Actor", "cweId": "CWE-200", "type": "CWE" } ] } ], "credits": [ { "lang": "en", "value": "Eunsoo Kim (Autonomous Code Security team at Microsoft)", "type": "finder" }, { "lang": "en", "value": "Stefan Eissing", "type": "remediation developer" } ], "x_generator": { "engine": "cvelib 1.8.0" } }, "adp": [ { "references": [ { "url": "https://hackerone.com/reports/3752888", "tags": [ "exploit" ] } ], "metrics": [ { "cvssV3_1": { "scope": "UNCHANGED", "version": "3.1", "baseScore": 7.5, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "NONE", "privilegesRequired": "NONE", "confidentialityImpact": "HIGH" } }, { "other": { "type": "ssvc", "content": { "timestamp": "2026-07-06T16:52:42.898546Z", "id": "CVE-2026-9545", "options": [ { "Exploitation": "poc" }, { "Automatable": "yes" }, { "Technical Impact": "partial" } ], "role": "CISA Coordinator", "version": "2.0.3" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-07-06T16:53:23.396Z" } } ] } }