Heap-based buffer overflow in iconvert.c in the bogolexer component in Bogofilter before 1.2.3 allows remote attackers to cause a denial of service (crash) and possibly execute arbitrary code via an email containing a base64 string that is decoded to incomplete multibyte characters.

Multiple buffer underflows in the base64 decoder in base64.c in (1) bogofilter and (2) bogolexer in bogofilter before 1.2.2 allow remote attackers to cause a denial of service (heap memory corruption and application crash) via an e-mail message with invalid base64 data that begins with an = (equals) character.