---
id: "CVE-2026-58265"
page: "https://infrastack.ai/live/CVE-2026-58265"
kind: "vulnerability"
aliases: ["CVE-2026-58265"]
title: "BACnet Stack: malformed BACnet/SC packet causes heap out-of-bounds read"
severity: "medium"
cvss: 6.5
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["bacnet", "building-automation", "c", "embedded", "package"]
not_affected_if: ["bacnet-sc-disabled", "versions-patched"]
published_at: "2026-11-13T16:19:12+00:00"
first_seen_at: "2026-11-13T16:47:34+00:00"
updated_at: "2026-11-13T16:48:49+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-58265", "first_seen_at": "2026-11-13T16:47:34+00:00"}]
exploit_sources: []
---

# BACnet Stack: malformed BACnet/SC packet causes heap out-of-bounds read

Link for people: https://infrastack.ai/live/CVE-2026-58265 (this .md is for agents)

BACnet Stack is an open source BACnet protocol C library for embedded systems. A remote BACnet/SC peer can send a crafted proprietary header option that makes the decoder read up to 3 bytes past a heap buffer, before any authentication.

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

## How to check

- Check the BACnet Stack version in your build or lockfile, e.g. the library's source tree or package manifest.
- Look for BACnet/SC support enabled in the build (bvlc_sc_decode_proprietary_option in the BACnet/SC code path).

## Fix

- Upgrade to `1.4.5`, `1.5.1`, or `1.6.0` on the matching release line.

## Timeline

- 2026-11-13T16:47:34+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-58265

## Documents

- [advisory] Vendor advisory: github.com https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-j66x-fr38-r7m5

## From the sources

BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to versions 1.4.5, 1.5.1, and 1.6.0, a BACnet/SC peer can trigger a heap out-of-bounds read (up to 3 bytes), pre-authentication, in the BACnet/SC header-option decoder. bvlc_sc_decode_proprietary_option() reads the vendor-id and option-type at fixed offsets [3],[4],[5] before checking the option's declared header length, and the option-list validator never enforces a minimum length for proprietary options. This issue has been patched in versions 1.4.5, 1.5.1, and 1.6.0.

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