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National Vulnerability Database

National Vulnerability Database

NVD

National Vulnerability Database
  1. Vulnerabilities

CVE-2026-21870 Detail

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.


Metrics

 
NVD enrichment efforts reference publicly available information to associate vector strings. CVSS information contributed by other sources is also displayed.
CVSS 4.0 Severity and Vector Strings:

NIST CVSS score
NIST: NVD
N/A
NVD assessment not yet provided.

References to Advisories, Solutions, and Tools

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URL Source(s) Tag(s)
https://github.com/bacnet-stack/bacnet-stack/commit/4e1176394a5ae50d2fd0b5790d9bff806dc08465 GitHub, Inc.
https://github.com/bacnet-stack/bacnet-stack/pull/1196 GitHub, Inc.
https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-pc83-wp6w-93mx GitHub, Inc.

Weakness Enumeration

CWE-ID CWE Name Source
CWE-193 Off-by-one Error GitHub, Inc.  

Change History

1 change records found show changes

Quick Info

CVE Dictionary Entry:
CVE-2026-21870
NVD Published Date:
02/13/2026
NVD Last Modified:
02/13/2026
Source:
GitHub, Inc.