{"id":"CVE-2026-9545","summary":"exposing HTTP/3 early data","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.","aliases":["CURL-CVE-2026-9545"],"modified":"2026-07-11T18:29:54.114949293Z","published":"2026-07-03T06:17:55.931Z","related":["openSUSE-SU-2026:11230-1","openSUSE-SU-2026:21272-1"],"database_specific":{"unresolved_ranges":[{"source":"AFFECTED_FIELD","extracted_events":[{"introduced":"8.20.0"},{"last_affected":"8.20.0"},{"introduced":"8.19.0"},{"last_affected":"8.19.0"},{"introduced":"8.18.0"},{"last_affected":"8.18.0"},{"introduced":"8.17.0"},{"last_affected":"8.17.0"},{"introduced":"8.16.0"},{"last_affected":"8.16.0"},{"introduced":"8.15.0"},{"last_affected":"8.15.0"},{"introduced":"8.14.1"},{"last_affected":"8.14.1"},{"introduced":"8.14.0"},{"last_affected":"8.14.0"},{"introduced":"8.13.0"},{"last_affected":"8.13.0"},{"introduced":"8.12.1"},{"last_affected":"8.12.1"},{"introduced":"8.12.0"},{"last_affected":"8.12.0"},{"introduced":"8.11.1"},{"last_affected":"8.11.1"},{"introduced":"8.11.0"},{"last_affected":"8.11.0"}]}],"cna_assigner":"curl","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/9xxx/CVE-2026-9545.json"},"references":[{"type":"WEB","url":"https://curl.se/docs/CVE-2026-9545.html"},{"type":"WEB","url":"https://curl.se/docs/CVE-2026-9545.json"},{"type":"WEB","url":"https://hackerone.com/reports/3752888"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/9xxx/CVE-2026-9545.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-9545"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/curl/curl","events":[{"introduced":"b1ef0e1a01c0bb6ee5367bd9c186a603bde3615a"},{"fixed":"68720b4837284335b2d63cb358f8f6ce65f5bc55"}],"database_specific":{"source":"CPE_RANGE","cpe":"cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:*","extracted_events":[{"introduced":"8.11.0"},{"fixed":"8.21.0"}]}}],"versions":["rc-8_21_0-3","rc-8_21_0-2","rc-8_21_0-1","curl-8_20_0","rc-8_20_0-3","rc-8_20_0-2","rc-8_20_0-1","curl-8_19_0","curl-8_18_0","curl-8_17_0","curl-8_16_0","curl-8_15_0","curl-8_14_1","curl-8_14_0","curl-8_13_0","curl-8_12_1","curl-8_12_0","curl-8_11_1","curl-8_11_0"],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-9545.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"}]}