CVE-2026-21870 (GCVE-0-2026-21870)

Vulnerability from cvelistv5 – Published: 2026-02-13 17:58 – Updated: 2026-02-13 18:19
VLAI
Title
The BACnet Protocol Stack library has an Off-by-one Stack-based Buffer Overflow in tokenizer_string
Summary
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.
Severity
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-02-13 18:19 UTC
CWE
Assigner
GitHub_M CNA
References
Impacted products
Vendor Product Version
bacnet-stack bacnet-stack Affected: <= 1.4.2
Affected: >= 1.5.0.rc1, <= 1.5.0.rc2
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