cvedb.io
CVE-2026-40279
LOW · CVSS 3.7
EPSS exploitation probability: 0%
Published 2026-04-21T17:16:54.853 · Last modified 2026-06-17T10:44:56.177

Summary

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 products

bacnetstack — bacnet_stack

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.