CVE-2026-52786
Received Received - Intake

Buffer Overflow in BACnet Stack EPICS Client

Vulnerability report for CVE-2026-52786, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-11-12

Last updated on: 2026-11-12

Assigner: GitHub, Inc.

Description

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, in the official apps/epics client tool on v1.6.0-rc1 (not in the generic BACnet RPM ACK decoder alone) a malicious BACnet/IP endpoint can reply to the EPICS tool’s legitimate ReadPropertyMultiple request with a syntactically valid ReadPropertyMultiple-ACK that contains more heading properties than the tool’s fixed local storage can hold. The response is decoded successfully and later consumed by ProcessRPMData(), which writes property values into a fixed global array using an unbounded linear index. This results in a reproducible global-buffer-overflow in apps/epics/main.c. This is a network-reachable memory corruption in the official epics tool’s response-processing path. The root cause is that apps/epics treats a remotely supplied variable-length RPM property list as if it were a trusted, fixed-size local heading-property set. This issue has been patched in versions 1.4.5, 1.5.1, and 1.6.0.

CVSS Scores

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Meta Information

Published
2026-11-12
Last Modified
2026-11-12
Generated
2026-11-12
AI Q&A
2026-11-12
EPSS Evaluated
N/A
NVD
EUVD

Affected Vendors & Products

Currently, no data is known.

Helpful Resources

Exploitability

CWE
CWE Icon
KEV
KEV Icon
CWE ID Description
CWE-129 The product uses untrusted input when calculating or using an array index, but the product does not validate or incorrectly validates the index to ensure the index references a valid position within the array.
CWE-787 The product writes data past the end, or before the beginning, of the intended buffer.

Attack-Flow Graph

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Executive Summary

CVE-2026-52786 is a buffer overflow vulnerability in the BACnet Stack's apps/epics client tool. A malicious BACnet/IP endpoint sends a crafted ReadPropertyMultiple-ACK response with more properties than the client's fixed storage can handle. The client's ProcessRPMData() function writes these properties into a fixed global array without proper bounds checking, causing a global buffer overflow.

Detection Guidance

To detect this vulnerability, monitor network traffic for BACnet/IP endpoints sending ReadPropertyMultiple-ACK responses with more than 7 properties. Use packet capture tools like tcpdump or Wireshark to inspect BACnet traffic for malformed responses. Check if your BACnet-stack version is below 1.4.5, 1.5.1, or 1.6.0.

Impact Analysis

This vulnerability allows remote attackers to cause crashes or denial of service by sending malicious BACnet/IP responses. It does not require privileges or user interaction. Exploiting it can lead to system instability, potential code execution, or unauthorized memory access in systems running affected versions of the BACnet Stack's epics tool.

Mitigation Strategies

Upgrade the BACnet-stack to versions 1.4.5, 1.5.1, or 1.6.0 or later. Disable the EPICS client tool if not in use. Implement network segmentation to isolate BACnet traffic. Monitor for unusual BACnet/IP responses with excessive properties.

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