CVE-20XX-?
agent?

CVE-2026-40279

3.7 LOW 0.2% exploit odds Fix listed Other Device

What it is

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.

At a glance

Exploitability
Can be exploited over the network without logging in. Limited direct impact.
Exploit odds
0.2% chance of exploitation in the next 30 days (EPSS).
Fix
A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

  1. PublishedDisclosed publicly on CVE.org and NVD
  2. Last updatedMost recent change to the record

Why it ranks here

Details

Published
Last modified
Exploit probability
0.2% · EPSS, next 30 days
Weakness
CWE-758
Record status
Analyzed

Affected

Attack profile CVSS 3.1 · 3.7

Attack vector
Network
Complexity
High
Privileges needed
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
Low
Raw vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-40279.md and follow it. Check whether this project is affected by CVE-2026-40279. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record