CVE-2026-46677

MEDIUM 6.5

BACnet Stack: Client-Side Out-of-Bounds Read in AtomicReadFile-ACK Record-Access Handling via RecordCount / fileData[] Mismatch

CVSS Score

6.5

EPSS Score

0.0%

EPSS Percentile

0th

BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to versions 1.4.4 and 1.5.1, there is a client-side out-of-bounds read in the AtomicReadFile-ACK record-access handling path. The issue is caused by a mismatch between a remote returnedRecordCount value and the fixed local fileData[] array capacity in BACNET_ATOMIC_READ_FILE_DATA. The ACK decode path preserves the remote RecordCount, discards storage for excess records without truncating that count, and a downstream sink later iterates over the original RecordCount and indexes fileData[i] out of bounds. This issue has been patched in versions 1.4.4 and 1.5.1.

CWE	CWE-125 CWE-130
Vendor	bacnet-stack
Product	bacnet-stack
Published	Nov 12, 2026

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CVSS v3 Breakdown

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Affected Versions

bacnet-stack / bacnet-stack

< 1.4.4 < 1.5.1

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/bacnet-stack/bacnet-stack/security/advisories/GHSA-rv5h-cxwq-q3mh github.com: https://github.com/bacnet-stack/bacnet-stack/pull/1344