CVE-2026-21870

Published Feb 13, 2026

Last updated 23 days ago

Overview

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.
Source
security-advisories@github.com
NVD status
Analyzed
Products
bacnet_stack

Risk scores

CVSS 3.1

Type
Secondary
Base score
5.5
Impact score
3.6
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Severity
MEDIUM

Weaknesses

security-advisories@github.com
CWE-193

Social media

Hype score
Not currently trending

Configurations