Bacnetstack: >> Bacnet Stack >> 0.2.4 Security Vulnerabilities
BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to 1.4.3, decode_signed32() in src/bacnet/bacint.c reconstructs a 32-bit signed integer from four APDU bytes using signed left shifts. When any of the four bytes has bit 7 set (value ≥ 0x80), the left-shift operation overflows a signed int32_t, which is undefined behavior per the C standard. This is flagged thousands of times per minute by UndefinedBehaviorSanitizer on any BACnet input containing signed-integer property values with high-bit-set bytes. This vulnerability is fixed in 1.4.3.
CVSS Score
3.7
EPSS Score
0.001
Published
2026-04-21
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.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-02-13
BACnet Stack before 1.3.2 has a decode function APDU buffer over-read in bacapp_decode_application_data in bacapp.c.
CVSS Score
9.1
EPSS Score
0.004
Published
2024-02-29