Description
BACnet Protocol Stack library provides a BACnet application layer, network layer and media access (MAC) layer communications services. In 1.4.2, 1.5.0.rc2, and earlier, an off-by-one stack-based buffer overflow in the ubasic interpreter causes a crash (SIGABRT) when processing string literals longer than the buffer limit. The tokenizer_string function in src/bacnet/basic/program/ubasic/tokenizer.c incorrectly handles null termination for maximum-length strings. It writes a null byte to dest[40] when the buffer size is only 40 (indices 0-39), triggering a stack overflow.
Problem types
Product status
>= 1.5.0.rc1, <= 1.5.0.rc2
References
github.com/...-stack/security/advisories/GHSA-pc83-wp6w-93mx
github.com/bacnet-stack/bacnet-stack/pull/1196
github.com/...ommit/4e1176394a5ae50d2fd0b5790d9bff806dc08465