CVE-2025-7964: Zigbee Router DOS Vulnerability

CVE-2025-7964 Overview

CVE-2025-7964 is a critical denial of service vulnerability affecting Zigbee network infrastructure. When a Zigbee Coordinator receives a malformed 802.15.4 MAC Data Request, it incorrectly sends a 'network leave' request to the Zigbee router, causing the router to enter a non-rejoinable state. This results in network disruption where end devices connected to the affected router cannot rejoin if a suitable parent is not available, requiring manual recommissioning to restore normal operation.

Critical Impact

Network-based attack can render Zigbee routers permanently non-functional until manual intervention, potentially disrupting entire IoT deployments including smart home automation, industrial sensors, and building management systems.

Affected Products

• Zigbee Coordinators processing 802.15.4 MAC Data Requests
• Zigbee Routers in affected network configurations
• End devices dependent on affected Zigbee routers

Discovery Timeline

• 2026-01-30 - CVE CVE-2025-7964 published to NVD
• 2026-02-04 - Last updated in NVD database

Technical Details for CVE-2025-7964

Vulnerability Analysis

This vulnerability stems from improper handling of values within the 802.15.4 MAC layer protocol processing (CWE-229: Improper Handling of Values). The Zigbee Coordinator fails to properly validate incoming MAC Data Request frames, and when encountering a malformed request, it erroneously interprets the packet in a way that triggers an unintended 'network leave' command to the originating or targeted Zigbee router.

The impact is particularly severe in Zigbee mesh networks where routers serve as intermediate nodes. When a router enters a non-rejoinable state, all end devices that rely on that router for network connectivity lose their communication path. The attack can be executed remotely over the network without authentication, making it accessible to any attacker within radio range of the Zigbee network.

Root Cause

The root cause is improper handling of values in the 802.15.4 MAC protocol implementation. The Coordinator's MAC layer processing logic does not adequately validate the structure and content of incoming Data Request frames. When malformed data is received, the parsing logic misinterprets certain fields, leading to the generation of an erroneous network leave command directed at a Zigbee router.

Attack Vector

The attack vector is network-based, exploiting the wireless 802.15.4 protocol that underlies Zigbee communications. An attacker within radio range of the target Zigbee network can craft and transmit malformed MAC Data Request frames to the Coordinator. The attack requires no authentication or prior network access, as it targets the low-level MAC layer processing before any application-level security measures are applied.

The vulnerability mechanism operates as follows: The attacker crafts a specially malformed 802.15.4 MAC Data Request frame with invalid or unexpected field values. When the Zigbee Coordinator receives this frame, its MAC layer processing incorrectly interprets the malformed data. This triggers the Coordinator to send an unintended 'network leave' command to a Zigbee router. The affected router processes this leave command and enters a non-rejoinable state. End devices connected through the router lose network connectivity and cannot automatically recover.

For technical details on the vulnerability, see the Silicon Labs Community Post.

Detection Methods for CVE-2025-7964

Indicators of Compromise

• Zigbee routers unexpectedly entering a disconnected or non-rejoinable state
• Multiple end devices simultaneously losing connectivity to the network
• Unusual 'network leave' commands originating from the Coordinator without user-initiated action
• Malformed or anomalous 802.15.4 MAC frames detected in wireless traffic captures

Detection Strategies

• Implement Zigbee network monitoring to detect unexpected network leave commands from Coordinators
• Monitor for unusual patterns of router disconnections that may indicate exploitation attempts
• Deploy wireless intrusion detection systems capable of analyzing 802.15.4 protocol traffic
• Log and alert on Coordinator-initiated network leave events that are not correlated with administrative actions

Monitoring Recommendations

• Enable detailed logging on Zigbee Coordinators to capture MAC layer events and network management commands
• Establish baseline behavior for network join/leave events to identify anomalous patterns
• Implement real-time alerting for router state changes indicating non-rejoinable conditions
• Consider deploying spectrum analyzers or 802.15.4 packet sniffers for deep protocol inspection in critical deployments

How to Mitigate CVE-2025-7964

Immediate Actions Required

• Review vendor advisories and apply firmware updates to Zigbee Coordinators when available
• Implement network segmentation to limit attacker access to Zigbee infrastructure where possible
• Monitor Zigbee networks for signs of exploitation and prepare recommissioning procedures
• Consider temporarily reducing the operational scope of critical Zigbee deployments until patches are applied

Patch Information

Refer to the Silicon Labs Community Post for vendor-specific guidance and patch availability. Organizations should contact their Zigbee device vendors to obtain firmware updates that address the improper handling of malformed MAC Data Requests.

Workarounds

• Implement physical security controls to limit unauthorized radio access to Zigbee network coverage areas
• Deploy redundant Zigbee routers to minimize single points of failure in the mesh network
• Prepare documented recommissioning procedures to rapidly restore affected routers to operational state
• Consider implementing network-level filtering where architecturally feasible to block malformed frames before reaching Coordinators

# Configuration example - Network monitoring setup for Zigbee environments
# Enable logging on Zigbee Coordinator (vendor-specific commands may vary)
# Monitor for unexpected network leave events
# Set up alerts for router state transitions to non-rejoinable status
# Document recommissioning procedures for rapid recovery