{"id":"UBUNTU-CVE-2017-3737","details":"OpenSSL 1.0.2 (starting from version 1.0.2b) introduced an \"error state\" mechanism. The intent was that if a fatal error occurred during a handshake then OpenSSL would move into the error state and would immediately fail if you attempted to continue the handshake. This works as designed for the explicit handshake functions (SSL_do_handshake(), SSL_accept() and SSL_connect()), however due to a bug it does not work correctly if SSL_read() or SSL_write() is called directly. In that scenario, if the handshake fails then a fatal error will be returned in the initial function call. If SSL_read()/SSL_write() is subsequently called by the application for the same SSL object then it will succeed and the data is passed without being decrypted/encrypted directly from the SSL/TLS record layer. In order to exploit this issue an application bug would have to be present that resulted in a call to SSL_read()/SSL_write() being issued after having already received a fatal error. OpenSSL version 1.0.2b-1.0.2m are affected. Fixed in OpenSSL 1.0.2n. OpenSSL 1.1.0 is not affected.","modified":"2026-04-22T12:19:21.831365Z","published":"2017-12-07T00:00:00Z","related":["USN-3512-1"],"upstream":["CVE-2017-3737"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2017-3737"},{"type":"REPORT","url":"https://www.openssl.org/news/secadv/20171207.txt"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-3512-1"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2017-3737"}],"affected":[{"package":{"name":"openssl","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/openssl@1.0.2g-1ubuntu4.10?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.0.2g-1ubuntu4.10"}]}],"versions":["1.0.2d-0ubuntu1","1.0.2d-0ubuntu2","1.0.2e-1ubuntu1","1.0.2f-2ubuntu1","1.0.2g-1ubuntu2","1.0.2g-1ubuntu3","1.0.2g-1ubuntu4","1.0.2g-1ubuntu4.1","1.0.2g-1ubuntu4.2","1.0.2g-1ubuntu4.4","1.0.2g-1ubuntu4.5","1.0.2g-1ubuntu4.6","1.0.2g-1ubuntu4.8","1.0.2g-1ubuntu4.9"],"ecosystem_specific":{"binaries":[{"binary_name":"libssl1.0.0","binary_version":"1.0.2g-1ubuntu4.10"},{"binary_name":"openssl","binary_version":"1.0.2g-1ubuntu4.10"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2017/UBUNTU-CVE-2017-3737.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N"},{"type":"Ubuntu","score":"medium"}]}