A flaw was found in the loadbuf function in formisc.c. When the buffer is too small, the function tries to resize it, but only by Bsize (=128) bytes. This is not necessarily enough and could cause denial of service.

References:

https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=876511

Buffer overflow in procmail before version 3.12 allows remote or local attackers to execute commands via expansions in the procmailrc configuration file.

Heap-based buffer overflow in formisc.c in formail in procmail 3.22 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via a crafted email header, related to "unbalanced quotes."

Race condition in signal handling of procmail 3.20 and earlier, when running setuid, allows local users to cause a denial of service or gain root privileges by sending a signal while a signal handling routine is already running.

A race condition in how procmail handles .procmailrc files allows a local user to read arbitrary files available to the user who is running procmail.