Hello,

we have a memory leak with stunnel 5.31 in server mode on Windows Server 2012. Page File Bytes of the stunnel process keep growing. The more traffic the faster it's growing, until memory is exhausted and client connects start to fail with:

2016.03.31 15:50:30 LOG3[main]: _beginthread: Exec format error (8) 2016.03.31 15:50:30 LOG3[main]: Connection rejected: create_client failed

I suspect it has something to do with clients not closing the connection correctly. We have a lot of connections ending like this:

2016.03.31 09:21:48 LOG3[5156]: SSL_shutdown: Connection reset by peer (WSAECONNRESET) (10054) 2016.03.31 09:21:48 LOG5[5156]: Connection reset: 239 byte(s) sent to SSL, 722 byte(s) sent to socket

Is my suspicion plausible? Can you recommend a change in the configuration to avoid this issue? Anything else I can do to debug?

The config looks something like this:

cert = C:\crt.pem key = C:\key.key ciphers = ALL:!DH:!aNULL:!eNULL:!LOW:!EXP socket = l:TCP_NODELAY=1 socket = r:TCP_NODELAY=1 verify = 2 CAfile = C:\All-In-One.pem

[test] accept = 23456 connect = 10.10.10.10