---
id: "CVE-2026-97692"
page: "https://infrastack.ai/live/CVE-2026-97692"
kind: "vulnerability"
aliases: ["CVE-2026-97692"]
title: "BACnet Stack: crafted BACnet/SC frame overflows memory before authentication"
severity: "high"
cvss: 7.7
epss: null
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["bacnet", "bacnet-sc", "building-automation", "c", "embedded", "package"]
not_affected_if: ["bacnet-sc-disabled", "patched-version"]
published_at: "2026-11-13T19:20:03+00:00"
first_seen_at: "2026-11-13T19:52:10+00:00"
updated_at: "2026-11-13T19:54:09+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-97692", "first_seen_at": "2026-11-13T19:52:10+00:00"}]
exploit_sources: []
---

# BACnet Stack: crafted BACnet/SC frame overflows memory before authentication

Link for people: https://infrastack.ai/live/CVE-2026-97692 (this .md is for agents)

BACnet Stack is a C library for building BACnet building-automation devices. A single crafted BACnet/SC frame makes the header-option decoder read and write past its buffers, and an attacker reaches it before authenticating.

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

## How to check

- Look for the `bacnet-stack` library in your build (for example `grep -ri bacnet` in your dependency manifests or vendored sources)
- Check the library version against the fixed versions below
- Confirm whether BACnet/SC (secure connect) support is compiled in and reachable from the network: unknown

## Fix

- `bacnet-stack` `1.4.6`, `1.5.2`, `1.6.1`, or `1.7.0` (the fixed versions named in the description; upgrade to the one on your release line)

## Timeline

- 2026-11-13T19:52:10+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-97692

## Documents

- [advisory] Vendor advisory: github.com https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-gr74-333w-7wg8

## From the sources

BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to versions 1.4.6, 1.5.2, and 1.6.1, the BACnet/SC message decoder walks the header-option list by following each option's MORE bit. Nothing rejects a list whose last option still has the MORE bit set, and the decode walk has no upper bound on how many options it processes. A single crafted BVLC-SC frame makes the walk advance one option past the end of the message and read message[message_len], one byte out of bounds. When the bytes after the message carry more MORE-set option markers, the walk keeps going: it runs past the fixed 4-entry option array and writes decoded option fields out of bounds. On the server that decode array is the static global bsc_dm, so the out-of-bounds write lands in adjacent BSS. Both faults are reachable before authentication, from the first frame a peer sends on a BACnet/SC connection, and the bytes that follow the message are the same peer's prior-frame data. This issue has been patched in versions 1.4.6, 1.5.2, 1.6.1, and 1.7.0.

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