CVE-2026-102076 in APOGEE MBC
Summary
by MITRE • 10/13/2026
A vulnerability has been identified in APOGEE MBC (PPC) (BACnet) (All versions), APOGEE MBC (PPC) (P2 Ethernet) (All versions), APOGEE MEC (PPC) (BACnet) (All versions), APOGEE MEC (PPC) (P2 Ethernet) (All versions), APOGEE PXC Compact (BACnet) (All versions < V3.5.7), APOGEE PXC Compact (P2 Ethernet) (All versions < V2.8.21), APOGEE PXC Modular (BACnet) (All versions < V3.5.7), APOGEE PXC Modular (P2 Ethernet) (All versions < V2.8.21), TALON TC Compact (BACnet) (All versions < V3.5.7), TALON TC Modular (BACnet) (All versions < V3.5.7). The affected product web service does not properly validate user-supplied input in upload code. This could allow an unauthenticated remote attacker to cause a denial of service.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 10/13/2026
The identified vulnerability affects multiple Honeywell APOGEE and TALON building automation system controllers, including the MBC, MEC, PXC Compact, PXC Modular, and TALon TC series in both BACnet and P2 Ethernet configurations. These devices are critical components within industrial control systems (ICS) that manage heating, ventilation, air conditioning, and other environmental controls. The core of this security flaw lies in the web service interface provided by these controllers for remote management and configuration. Specifically, the vulnerability resides in the input validation logic associated with the code upload functionality. This feature is designed to allow authorized administrators to push firmware updates or control scripts to the device from a central server or workstation. However, the implementation fails to adequately sanitize or validate user-supplied data before processing it during the upload operation.
From a technical perspective, this represents a classic case of improper input validation leading to resource exhaustion or application crash conditions. When an unauthenticated remote attacker interacts with the web service and submits malformed or excessively large payloads through the code upload endpoint, the system does not perform sufficient checks on data size, structure, or type before attempting to process it. This lack of robust boundary checking can lead to memory corruption, stack overflow, or infinite loops within the controller's operating environment. Because the vulnerability allows interaction by unauthenticated users, there is no requirement for valid credentials to exploit this flaw. The attacker simply needs network access to the management interface and knowledge of the endpoint URL to trigger the denial of service condition.
The operational impact of this vulnerability is significant due to its potential to disrupt building automation operations. A successful exploitation results in a denial of service, meaning the affected controller becomes unresponsive or crashes repeatedly. In the context of HVAC systems, this can lead to immediate loss of environmental control capabilities. For commercial buildings, hospitals, or data centers relying on these controllers for climate regulation and energy management, such outages can result in substantial financial losses, discomfort for occupants, or even safety risks if critical cooling fails. Furthermore, because the device may require a manual reboot to restore service, an attacker could potentially launch repeated attacks to keep the system offline indefinitely, effectively taking the building's automation infrastructure out of commission without gaining persistent access or data exfiltration capabilities.
This vulnerability aligns with CWE-20 Improper Input Validation and is often associated with CWE-400 Uncontrolled Resource Consumption when it leads to denial of service conditions. In terms of attack vectors, this falls under the MITRE ATT&CK framework category of Impact, specifically resource hijacking or disruption services. The fact that no authentication is required places this in a high-risk category for devices exposed on internal networks where lateral movement might be easier if other security controls are weak. It highlights the common challenge in ICS environments where legacy systems often prioritize functionality and ease of integration over rigorous security hygiene, leaving management interfaces accessible to any entity with network connectivity.
Mitigation strategies must focus on both immediate remediation and long-term architectural improvements. The primary solution is to apply the vendor-recommended firmware updates for all affected versions immediately. For devices running APOGEE PXC Compact or Modular systems below version V3.5.7, updating to at least that version resolves the issue in BACnet implementations. Similarly, P2 Ethernet variants of these models require an update to at least version V2.8.21. Devices such as the MBC and MEC series are affected across all versions, implying a patch may need specific deployment or configuration changes if not addressed by a simple version bump. If immediate patching is not feasible due to operational constraints, network segmentation should be enforced strictly. The management interfaces of these controllers must never be exposed directly to untrusted networks such as the public internet and should reside on isolated VLANs accessible only from authorized administrative workstations or secure jump hosts. Additionally, implementing strict firewall rules that limit access to port 80 or other web service ports solely by IP address can provide a critical layer of defense in depth against remote exploitation attempts while patches are being prepared for deployment across the facility infrastructure.