Can confirm that stunnel4 (5.44-1ubuntu3) crashes every few hours on a 18.04 LTS system (about to be upgraded) when connected from a 22.04 LTS system (5.63-1build1). The network between the two only allows their respective packets, and the 22.04 LTS system was recently a 18.04 LTS system. The 18.04 LTS didn't have stunnel4 crash ever until the other system upgraded. I was going to upgrade the 18.04 LTS anyway, but this bug report thread convinced me to upgrade ASAP (I'd rather not rely on restarting after every crash via systemd unit file).
If you want to reproduce the error, try an 18.04 VM and 22.04, and start a data transfer. Shouldn't take too long.
Can confirm that stunnel4 (5.44-1ubuntu3) crashes every few hours on a 18.04 LTS system (about to be upgraded) when connected from a 22.04 LTS system (5.63-1build1). The network between the two only allows their respective packets, and the 22.04 LTS system was recently a 18.04 LTS system. The 18.04 LTS didn't have stunnel4 crash ever until the other system upgraded. I was going to upgrade the 18.04 LTS anyway, but this bug report thread convinced me to upgrade ASAP (I'd rather not rely on restarting after every crash via systemd unit file).
If you want to reproduce the error, try an 18.04 VM and 22.04, and start a data transfer. Shouldn't take too long.