CVE-2026-21870

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.
Configurations

Configuration 1 (hide)

OR cpe:2.3:a:bacnetstack:bacnet_stack:*:*:*:*:*:*:*:*
cpe:2.3:a:bacnetstack:bacnet_stack:1.5.0:rc1:*:*:*:*:*:*
cpe:2.3:a:bacnetstack:bacnet_stack:1.5.0:rc2:*:*:*:*:*:*

History

17 Jun 2026, 10:19

Type Values Removed Values Added
References () https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-pc83-wp6w-93mx - Vendor Advisory, Exploit () https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-pc83-wp6w-93mx - Exploit, Vendor Advisory
Summary
  • (es) La librería de la pila de protocolo BACnet proporciona servicios de comunicación de capa de aplicación, capa de red y capa de acceso al medio (MAC) de BACnet. En las versiones 1.4.2, 1.5.0.rc2 y anteriores, un desbordamiento de búfer basado en pila por un byte en el intérprete ubasic provoca un fallo (SIGABRT) al procesar literales de cadena más largos que el límite del búfer. La función tokenizer_string en src/bacnet/basic/program/ubasic/tokenizer.c maneja incorrectamente la terminación nula para cadenas de longitud máxima. Escribe un byte nulo en dest[40] cuando el tamaño del búfer es solo 40 (índices 0-39), desencadenando un desbordamiento de pila.

18 Feb 2026, 18:49

Type Values Removed Values Added
First Time Bacnetstack bacnet Stack
Bacnetstack
References () https://github.com/bacnet-stack/bacnet-stack/commit/4e1176394a5ae50d2fd0b5790d9bff806dc08465 - () https://github.com/bacnet-stack/bacnet-stack/commit/4e1176394a5ae50d2fd0b5790d9bff806dc08465 - Patch
References () https://github.com/bacnet-stack/bacnet-stack/pull/1196 - () https://github.com/bacnet-stack/bacnet-stack/pull/1196 - Patch
References () https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-pc83-wp6w-93mx - () https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-pc83-wp6w-93mx - Vendor Advisory, Exploit
CPE cpe:2.3:a:bacnetstack:bacnet_stack:1.5.0:rc1:*:*:*:*:*:*
cpe:2.3:a:bacnetstack:bacnet_stack:1.5.0:rc2:*:*:*:*:*:*
cpe:2.3:a:bacnetstack:bacnet_stack:*:*:*:*:*:*:*:*

13 Feb 2026, 18:16

Type Values Removed Values Added
New CVE

Information

Published : 2026-02-13 18:16

Updated : 2026-06-17 10:19


NVD link : CVE-2026-21870

Mitre link : CVE-2026-21870

CVE.ORG link : CVE-2026-21870


JSON object : View

Products Affected

bacnetstack

  • bacnet_stack
CWE
CWE-193

Off-by-one Error