Mutt version 1.5.19 introduced a support for intermediate CA certs, available when mutt is linked against both OpenSSL and GnuTLS, added via upstream commits: http://dev.mutt.org/trac/changeset/5621:5db868a874b6/mutt_ssl.c http://dev.mutt.org/trac/changeset/5623:7d0583e0315d/mutt_ssl_gnutls.c Miroslav Lichvar noticed that a certificate chain validation was not implemented properly. Individual certificates in the chain where checked and accepted, but the chain as a whole as not validated properly. Issue was addressed via following upstream patches: http://dev.mutt.org/trac/changeset?new=5870:dc9ec900c657@mutt_ssl.c&old=5699:1238dff54a15@mutt_ssl.c http://dev.mutt.org/trac/changeset?new=5853:0b13183e40e0@mutt_ssl_gnutls.c&old=5699:1238dff54a15@mutt_ssl_gnutls.c
This issue only affects mutt 1.5.19, version of mutt shipped in Red Hat Enterprise Linux 3, 4, and 5, and Fedora 9 and 10 are not affected by this problem.
mutt-1.5.19-5.fc11 has been pushed to the Fedora 11 stable repository. If problems still persist, please make note of it in this bug report.