CVE-2026-21870
The BACnet Protocol Stack library has an Off-by-one Stack-based Buffer Overflow in tokenizer_string
- State
- Published
- Severity
- 5.5 Medium
- Published
- Feb 13, 2026
- Updated
- Feb 13, 2026
- Reserved
- Jan 5, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 5.5 Medium | CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H | GitHub_M |
Weaknesses
- CWE-193 Off-by-one Error
Affected Products
| Product | Versions |
|---|---|
bacnet-stackbacnet-stack |
|
References
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