The Erlang ssl module is vulnerable to a cryptographic attack against the RSA key exchange. This has been fixed in OTP 126.96.36.199, 188.8.131.52, 20.1.7.
Please update. Currently erlang 19.1 is stable on most archs. Depending on whether you want to continue supporting 18/19 we may need updates in multiple branches.
20.3 should get this fixed (and stabilizing it with net-im/ejabberd-17.04-r2 will finally allow to drop old branches)
Already fixed, repository is clean. All done!