CVEvulnerability

CVE-2026-40279

3.7 LOW Published 2026-04-21 Modified 2026-06-17 Official page ↗
Status
Analyzed
Published
2026-04-21
Last modified
2026-06-17
Assigner
[email protected]
CVSS 3.1 ([email protected])
3.7 LOW — CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
Weaknesses
CWE-758

Description

BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to 1.4.3, decode_signed32() in src/bacnet/bacint.c reconstructs a 32-bit signed integer from four APDU bytes using signed left shifts. When any of the four bytes has bit 7 set (value ≥ 0x80), the left-shift operation overflows a signed int32_t, which is undefined behavior per the C standard. This is flagged thousands of times per minute by UndefinedBehaviorSanitizer on any BACnet input containing signed-integer property values with high-bit-set bytes. This vulnerability is fixed in 1.4.3.

Affected configurations

• bacnetstack bacnet stack (< 1.4.3)

Related

Weakness · CWE (1)

  • CWE-758 Reliance on Undefined, Unspecified, or Implementation-Defined Behavior weakness

References