An issue was discovered in Ruby through 2.6.7, 2.7.x through 2.7.3, and 3.x through 3.0.1. Net::IMAP does not raise an exception when StartTLS fails with an an unknown response, which might allow man-in-the-middle attackers to bypass the TLS protections by leveraging a network position between the client and the registry to block the StartTLS command, aka a "StartTLS stripping attack."
{ "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro", "binaries": [ { "binary_version": "2.3.1-2~ubuntu16.04.16+esm1", "binary_name": "libruby2.3" }, { "binary_version": "2.3.1-2~ubuntu16.04.16+esm1", "binary_name": "ruby2.3" }, { "binary_version": "2.3.1-2~ubuntu16.04.16+esm1", "binary_name": "ruby2.3-dev" }, { "binary_version": "2.3.1-2~ubuntu16.04.16+esm1", "binary_name": "ruby2.3-tcltk" } ] }