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CVE-2026-97692

BACnet Stack: pre-auth out-of-bounds read that escalates to an out-of-bounds write into global memory

  • High 7.7

Description

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.

Key facts

Published
13 Nov 2026
Last changed
13 Nov 2026
Assigned by
GitHub_M
EPSS
0.497% likely to be exploited in the next 30 days, higher than 43.186% of CVEs (scores for 15 Nov 2026)

Severity scores

Each score is shown as its source gave it. They are not averaged or merged.

  • 7.7CVSS 3.1, Highfrom the CNA (GitHub_M)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:H/A:H

Historical context and remediation

This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.

No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.

No explicit remediation statement is available on this page yet. Consult the original record and vendor references before choosing a fix.

Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.

Read the original CVE record.

Affected products

VendorProductVersions
bacnet-stackbacnet-stack
  • < 1.4.6 (affected)
  • >= 1.5.0, < 1.5.2 (affected)
  • >= 1.6.0, < 1.6.1 (affected)

Timeline

  1. 13 Nov 2026 Published

Weakness

References