{"id":"USN-4233-2","aliases":[],"status":"published","title":"gnutls28 update","description":"USN-4233-1 disabled SHA1 being used for digital signature operations in\nGnuTLS. In certain network environments, certificates using SHA1 may still\nbe in use. This update adds the %VERIFY_ALLOW_BROKEN and\n%VERIFY_ALLOW_SIGN_WITH_SHA1 priority strings that can be used to\ntemporarily re-enable SHA1 until certificates can be replaced with a\nstronger algorithm.\n\nOriginal advisory details:\n\n As a security improvement, this update marks SHA1 as being untrusted for\n digital signature operations.","facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"published":"2020-01-23T16:57:09Z","modified":"2026-04-22T09:51:07Z","fixes":[{"ecosystem":"Ubuntu:16.04:LTS","package":"gnutls28","fixed_in":["3.4.10-4ubuntu1.7"],"sources":["osv"]},{"ecosystem":"Ubuntu:18.04:LTS","package":"gnutls28","fixed_in":["3.5.18-1ubuntu1.3"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Ubuntu:16.04:LTS","package":"gnutls28","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.4.10-4ubuntu1.7"}]}],"versions":["3.3.15-5ubuntu2","3.3.18-1ubuntu1","3.3.20-1ubuntu1","3.4.9-2ubuntu1","3.4.10-4ubuntu1","3.4.10-4ubuntu1.1","3.4.10-4ubuntu1.2","3.4.10-4ubuntu1.3","3.4.10-4ubuntu1.4","3.4.10-4ubuntu1.5","3.4.10-4ubuntu1.6"]},{"source":"osv","ecosystem":"Ubuntu:18.04:LTS","package":"gnutls28","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.5.18-1ubuntu1.3"}]}],"versions":["3.5.8-6ubuntu3","3.5.17-1ubuntu1","3.5.17-1ubuntu3","3.5.18-1ubuntu1","3.5.18-1ubuntu1.1","3.5.18-1ubuntu1.2"]}],"references":[{"url":"https://ubuntu.com/security/notices/USN-4233-2","tags":["advisory"]},{"url":"https://launchpad.net/bugs/1860656","tags":["report"]}],"sources":{"osv":[{"id":"USN-4233-2","title":"gnutls28 update","description":"USN-4233-1 disabled SHA1 being used for digital signature operations in\nGnuTLS. In certain network environments, certificates using SHA1 may still\nbe in use. This update adds the %VERIFY_ALLOW_BROKEN and\n%VERIFY_ALLOW_SIGN_WITH_SHA1 priority strings that can be used to\ntemporarily re-enable SHA1 until certificates can be replaced with a\nstronger algorithm.\n\nOriginal advisory details:\n\n As a security improvement, this update marks SHA1 as being untrusted for\n digital signature operations.\n","status":"published","published":"2020-01-23T16:57:09Z","modified":"2026-04-22T09:51:07.827113Z","updated_at":"2026-11-02T16:58:14.547547Z"}]}}