{"id":"UBUNTU-CVE-2021-22890","details":"curl 7.63.0 to and including 7.75.0 includes vulnerability that allows a malicious HTTPS proxy to MITM a connection due to bad handling of TLS 1.3 session tickets. When using a HTTPS proxy and TLS 1.3, libcurl can confuse session tickets arriving from the HTTPS proxy but work as if they arrived from the remote server and then wrongly \"short-cut\" the host handshake. When confusing the tickets, a HTTPS proxy can trick libcurl to use the wrong session ticket resume for the host and thereby circumvent the server TLS certificate check and make a MITM attack to be possible to perform unnoticed. Note that such a malicious HTTPS proxy needs to provide a certificate that curl will accept for the MITMed server for an attack to work - unless curl has been told to ignore the server certificate check.","modified":"2026-04-22T12:48:14.902338Z","published":"2021-03-31T06:00:00Z","related":["USN-4898-1"],"upstream":["CVE-2021-22890"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2021-22890"},{"type":"REPORT","url":"https://curl.se/docs/CVE-2021-22890.html"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-4898-1"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2021-22890"}],"affected":[{"package":{"name":"curl","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/curl@7.68.0-1ubuntu2.5?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"7.68.0-1ubuntu2.5"}]}],"versions":["7.65.3-1ubuntu3","7.65.3-1ubuntu4","7.66.0-1ubuntu1","7.67.0-2ubuntu1","7.68.0-1ubuntu1","7.68.0-1ubuntu2","7.68.0-1ubuntu2.1","7.68.0-1ubuntu2.2","7.68.0-1ubuntu2.4"],"ecosystem_specific":{"availability":"No subscription required","binaries":[{"binary_name":"curl","binary_version":"7.68.0-1ubuntu2.5"},{"binary_version":"7.68.0-1ubuntu2.5","binary_name":"libcurl3-gnutls"},{"binary_name":"libcurl3-nss","binary_version":"7.68.0-1ubuntu2.5"},{"binary_version":"7.68.0-1ubuntu2.5","binary_name":"libcurl4"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-22890.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N"},{"type":"Ubuntu","score":"medium"}]}