I noticed a heap overflow in procmail when parsing addresses with unbalanced quotes. I encountered this by accident when trying to organize a large usenet archive, this post to rec.arts.poems causes formail to crash. https://groups.google.com/forum/message/raw?msg=alt.arts.poetry.comments/DCuLO3qzovI/CZk15MlfqNkJ I've attached an mbox for reference. $ formail -s < mbox > /dev/null *** Error in `formail': free(): invalid next size (fast): 0x00007f103784a080 *** Segmentation fault (core dumped) $ rpm -q procmail procmail-3.22-33.fc20.x86_64 It looks like the fix is --- formisc.c 2013-08-04 00:13:33.000000000 -0700 +++ formisc.c 2014-09-03 11:42:25.986002396 -0700 @@ -84,12 +84,11 @@ case '"':*target++=delim='"';start++; } ;{ int i; - do + while(*start) if((i= *target++= *start++)==delim) /* corresponding delimiter? */ break; else if(i=='\\'&&*start) /* skip quoted character */ *target++= *start++; - while(*start); /* anything? */ } hitspc=2; } Tavis.