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.
References
| Link | Resource |
|---|---|
| https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-326g-j95f-gmxv | Exploit Mitigation Vendor Advisory |
| https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-326g-j95f-gmxv | Exploit Mitigation Vendor Advisory |
Configurations
History
27 Apr 2026, 19:49
| Type | Values Removed | Values Added |
|---|---|---|
| CPE | cpe:2.3:a:bacnetstack:bacnet_stack:*:*:*:*:*:*:*:* | |
| First Time |
Bacnetstack bacnet Stack
Bacnetstack |
|
| References | () https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-326g-j95f-gmxv - Exploit, Mitigation, Vendor Advisory |
21 Apr 2026, 20:16
| Type | Values Removed | Values Added |
|---|---|---|
| References | () https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-326g-j95f-gmxv - |
21 Apr 2026, 17:16
| Type | Values Removed | Values Added |
|---|---|---|
| New CVE |
Information
Published : 2026-04-21 17:16
Updated : 2026-04-27 19:49
NVD link : CVE-2026-40279
Mitre link : CVE-2026-40279
CVE.ORG link : CVE-2026-40279
JSON object : View
Products Affected
bacnetstack
- bacnet_stack
CWE
CWE-758
Reliance on Undefined, Unspecified, or Implementation-Defined Behavior