Operating system: Debian 9
OS version: 9

I have updated some servers today, the update also included most recent versions of Virtualmin, Webmin and Usermin.

Now I get the following error on all servers when I try to renew a Letsencrypt certificate (automatic renewal also produces the error=:

Requesting a certificate for xyz.com from Let’s Encrypt …

HTTP/1.0 500 Perl execution failed Server: MiniServ/1.973 Date: Sun, 14 Mar 2021 15:25:37 GMT Content-type: text/html; Charset=utf-8 Connection: close


panic: attempt to copy freed scalar 55d269a150e8 to 55d268a60298 at /usr/share/webmin/web-lib-funcs.pl line 3353.

The problem is really exactly the same on all updated servers.

So I have no idea how to fix this, and already getting complaints because of expired certificates (also found out previous version did not auto renew some certificates, but without errors visible to me).

Thanks for any help!

See here Let's Encrypt (manual) renew: Perl Execution Failed in web-lib-funcs.pl

It seems, that this error appears only on Debian 9 hosts.

For anyone who’s seeing this, can you try applying this patch and let me know if it still happens :


Hi Jamie,

I have made the changes on two servers, and after restarting webmin the certificate generation works without errors.

I have also done some changes yesterday that allowed the certificates to be renewed (and I don’t use IPv6 anyway):

# Perform IPv6 DNS lookup
#       my @ai = getaddrinfo($host, undef, AF_INET6(), SOCK_STREAM);
#       while(@ai) {
#               (undef, undef, undef, $inaddr, undef, @ai) = @ai;
#               if ($inaddr) {
#                       my $addr;
#                       (undef, $addr) = unpack_sockaddr_in6($inaddr);
#                       push(@rv, inet_ntop(AF_INET6(), $addr));
#                       }
#               }
 @rv = ( );
return wantarray ? @rv : $rv[0];

but of course I don’t know what else could go wrong with this, so I will of course apply your solution everywhere (but at least I was able to renew a few certificates with my workaround)

Thanks for your help!

Yes it is working debian stretch 9.13 webmin 1.973

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