Integer Overflow Vulnerability in BACnet Stack for Embedded Systems
CVE-2026-40279

3.7LOW

Key Information:

Vendor

Bacnet-stack

Status
Bacnet-stack
Vendor
CVE Published:
21 April 2026

What is CVE-2026-40279?

The BACnet Stack is an open-source protocol stack for embedded systems that faced an integer overflow issue in its decode_signed32() function before version 1.4.3. This function reconstructs a 32-bit signed integer from four APDU bytes using signed left shifts. If any byte has its highest bit set (value ≥ 0x80), it causes a left-shift overflow on a signed int32_t, resulting in undefined behavior, which is flagged repeatedly by UndefinedBehaviorSanitizer on affected inputs. This vulnerability is addressed in version 1.4.3, ensuring safer processing of signed integer property values.

Affected Version(s)

bacnet-stack < 1.4.3

References

https://github.com/bacnet-stack/bacnet-stack/security/adv...
x_refsource_CONFIRM

CVSS V3.1

Score:
3.7
Severity:
LOW
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
High
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.