---
id: "CVE-2026-46676"
page: "https://infrastack.ai/live/CVE-2026-46676"
kind: "vulnerability"
aliases: ["CVE-2026-46676"]
title: "BACnet Stack: uninitialized value lets crafted file-read requests corrupt responses"
severity: "medium"
cvss: 5.3
epss: null
exploited: false
status: "open"
category: "package"
products: [{"name": "bacnet-stack", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["bacnet", "building-automation", "c", "embedded", "package"]
not_affected_if: ["bacnet-not-exposed", "no-record-access-handling"]
published_at: "2026-11-12T20:18:39+00:00"
first_seen_at: "2026-11-12T20:40:26+00:00"
updated_at: "2026-11-12T20:42:24+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-46676", "first_seen_at": "2026-11-12T20:40:26+00:00"}]
exploit_sources: []
---

# BACnet Stack: uninitialized value lets crafted file-read requests corrupt responses

Link for people: https://infrastack.ai/live/CVE-2026-46676 (this .md is for agents)

BACnet Stack is an open source BACnet protocol C library used in embedded building-automation devices. A crafted unauthenticated AtomicReadFile request can corrupt the length and payload boundary of the encoded response, because an uninitialized value is used.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:bacnet-stack affected range not listed fixed no fixed version listed

## How to check

- Check the bacnet-stack version in your build or vendored source, for example `grep -ri "bacnet" package.json` or your embedded firmware's version string.
- Look for BACnet services exposed on the network, where AtomicReadFile is handled.

## Fix

- bacnet-stack `1.4.4` for the 1.4.x line
- bacnet-stack `1.5.1` for the 1.5.x line

## Timeline

- 2026-11-12T20:40:26+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-46676

## Documents

- [advisory] Vendor advisory: github.com https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-2fwp-32cj-g3x4

## From the sources

BACnet Stack is a BACnet open source protocol stack C library for embedded systems. From versions 1.4.0 to before 1.4.4, and 1.5.0 to before 1.5.1, an uninitialized value use vulnerability in bacnet-stack's AtomicReadFile record-access ACK encoder allows unauthenticated remote attackers to corrupt the encoded OCTET STRING length and payload boundary in network responses by sending a crafted AtomicReadFile request that reaches a successful record-access path. This issue has been patched in versions 1.4.4 and 1.5.1.

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