I made a more radical decision, I upgraded to 20.04 LTS (focal), installed Stunnel 5.56 and so far I have not had any crashes. For those who want and can do this upgrade, I recommend them, since not only is Stunnel updated, but also OpenSSL. For newbies like me I share the commands:
sudo apt update sudo apt upgrade sudo do-release-upgrade -d After that the Stunnel looks like this: root@ip-xxxxx:/home/ubuntu# stunnel -v [ ] Clients allowed=500 [.] stunnel 5.56 on x86_64-pc-linux-gnu platform [.] Compiled with OpenSSL 1.1.1c 28 May 2019 [.] Running with OpenSSL 1.1.1f 31 Mar 2020 [.] Threading:PTHREAD Sockets:POLL,IPv6,SYSTEMD TLS:ENGINE,FIPS,OCSP,PSK,SNI Auth:LIBWRAP [ ] errno: (*__errno_location ()) [!] Invalid configuration file name "-v" [!] realpath: No such file or directory (2) [ ] Deallocating section defaults -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1847275 Title: stunnel4: "INTERNAL ERROR: Bad magic at ssl.c, line 117" - DoS vulnerability To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/stunnel4/+bug/1847275/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs