CVE-2026-62975
Received Received - Intake

Heap Out-of-Bounds Read in BACnet Stack

Vulnerability report for CVE-2026-62975, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-11-13

Last updated on: 2026-11-13

Assigner: GitHub, Inc.

Description

BACnet Stack is a BACnet open source protocol stack C library for embedded systems. Prior to version 1.5.1, the RAMFS-backed FILE implementation accepts AtomicWriteFile(record-access) requests that replace existing records with caller-controlled content. If a client replaces a record with shorter data, the backend can shrink the heap allocation and then continue processing with a trailing-copy length derived from the old layout. During that replace path, the RAMFS backend computes the trailing-copy length from the old file layout, then shrinks the heap allocation, and finally uses the stale length in memmove(). As a result, the source range of that memmove() can extend beyond the end of the reallocated heap buffer, producing a heap out-of-bounds read. This issue has been patched in versions 1.5.1 and 1.6.0.

CVSS Scores

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Meta Information

Published
2026-11-13
Last Modified
2026-11-13
Generated
2026-11-13
AI Q&A
2026-11-13
EPSS Evaluated
N/A
NVD
EUVD

Affected Vendors & Products

Showing 2 associated CPEs
Vendor Product Version / Range
bacnet_stack bacnet_stack to 1.5.1 (inc)
bacnet_stack bacnet_stack to 1.6.0 (inc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-125 The product reads data past the end, or before the beginning, of the intended buffer.

Attack-Flow Graph

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Executive Summary

This vulnerability affects the BACnet Stack library before version 1.5.1. It involves a flaw in the RAMFS-backed FILE implementation where AtomicWriteFile(record-access) requests can replace existing records with shorter data. This causes the heap allocation to shrink, but the system incorrectly uses stale length values in memory operations, leading to a heap out-of-bounds read.

Detection Guidance

Detecting this vulnerability requires checking the BACnet Stack version in use. If you are running a version prior to 1.5.1, the system is vulnerable. Use commands like 'bacnet-stack --version' or inspect installed packages to verify the version.

Impact Analysis

An attacker could exploit this to read memory outside the intended buffer, potentially exposing sensitive data or causing crashes. Systems using vulnerable BACnet Stack versions may face instability or unauthorized information disclosure.

Mitigation Strategies

Upgrade the BACnet Stack to version 1.5.1 or later. If upgrading is not immediately possible, restrict network access to BACnet services or disable AtomicWriteFile(record-access) requests as a temporary workaround.

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