Description of problem:

Program terminated with signal 11, Segmentation fault.
#0  mx_update_context (ctx=0x16b56c0, new_messages=<optimized out>) at mx.c:1542
1542	      h->security = crypt_query (h->content);
(gdb) bt
#0  mx_update_context (ctx=0x16b56c0, new_messages=<optimized out>) at mx.c:1542
#1  0x0000000000493e96 in imap_read_headers (idata=0x16d45e0, msgbegin=<optimized out>, 
    msgend=229) at message.c:376
#2  0x0000000000491823 in imap_open_mailbox (ctx=0x16b56c0) at imap.c:756
#3  0x0000000000442c55 in mx_open_mailbox (path=<optimized out>, flags=0, pctx=0x0) at mx.c:661
#4  0x00000000004074dc in main (argc=1, argv=<optimized out>) at main.c:1017

Version-Release number of selected component (if applicable):

mutt-1.5.21-3.fc15.x86_64

How reproducible:

Happened once so far. Hasn't happened at least one other time I've tried the same thing.

Steps to Reproduce:
1. Have fetchmail pulling an IMAP inbox
2. Simultaneously, run mutt -f imaps://<that inbox>/