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.
Weakness
A product calculates or uses an incorrect maximum or minimum value that is 1 more, or 1 less, than the correct value.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Bacnet_stack | Bacnetstack | * | 1.4.2 (including) |
| Bacnet_stack | Bacnetstack | 1.5.0-rc1 (including) | 1.5.0-rc1 (including) |
| Bacnet_stack | Bacnetstack | 1.5.0-rc2 (including) | 1.5.0-rc2 (including) |