{"id":"UBUNTU-CVE-2026-9545","details":"In this scenario, libcurl first uses a proper HTTP/3 server for the initial transfers, and when it makes a second transfer to the same site it has been replaced by the attacker's impostor machine - without a valid certificate. When libcurl returns to the hostname the second time with a cached SSL session (`CURLOPT_SSL_SESSIONID_CACHE` is not disabled) and early data enabled (the `CURLSSLOPT_EARLYDATA` bit is set in `CURLOPT_SSL_OPTIONS`), libcurl might send off the second request's bytes on that new connection *before* enforcing the certificate verification failure. Potentially leaking sensitive information.","modified":"2026-07-09T17:16:51.025175049Z","published":"2026-06-24T14:00:00Z","related":["USN-8487-1"],"upstream":["CVE-2026-9545"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-9545"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-9545"},{"type":"REPORT","url":"https://curl.se/L7HzKXisfJ/CVE-2026-9545.md"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-8487-1"}],"affected":[{"package":{"name":"curl","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/curl?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"8.14.1-2ubuntu1.4"}]}],"versions":["8.12.1-3ubuntu1","8.13.0-5ubuntu1","8.14.1-1ubuntu2","8.14.1-1ubuntu3","8.14.1-2ubuntu1","8.14.1-2ubuntu1.1","8.14.1-2ubuntu1.2","8.14.1-2ubuntu1.3"],"ecosystem_specific":{"availability":"No subscription required","priority_reason":"Upstream defined this as low severity","binaries":[{"binary_name":"curl","binary_version":"8.14.1-2ubuntu1.4"},{"binary_name":"libcurl3t64-gnutls","binary_version":"8.14.1-2ubuntu1.4"},{"binary_name":"libcurl4t64","binary_version":"8.14.1-2ubuntu1.4"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-9545.json"}},{"package":{"name":"curl","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/curl?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"8.18.0-1ubuntu2.2"}]}],"versions":["8.14.1-2ubuntu1","8.17.0-1ubuntu1","8.18.0-1ubuntu1","8.18.0-1ubuntu2","8.18.0-1ubuntu2.1"],"ecosystem_specific":{"availability":"No subscription required","priority_reason":"Upstream defined this as low severity","binaries":[{"binary_name":"curl","binary_version":"8.18.0-1ubuntu2.2"},{"binary_name":"libcurl3t64-gnutls","binary_version":"8.18.0-1ubuntu2.2"},{"binary_version":"8.18.0-1ubuntu2.2","binary_name":"libcurl4t64"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-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"},{"type":"Ubuntu","score":"low"}]}