imap-uw -- mailbox name handling remote buffer vulnerability

FrSIRT reports:

A vulnerability has been identified in UW-IMAP, which could
be exploited by remote attackers to execute arbitrary commands.
This flaw is due to a stack overflow error in the
“mail_valid_net_parse_work()” [src/c-client/mail.c] function that
does not properly handle specially crafted mailbox names containing
a quote (") character, which could be exploited by authenticated
remote attackers to execute arbitrary commands with the privileges
of the IMAP server.