CVE-2024-23938: Silabs Gecko OS RCE Vulnerability

CVE-2024-23938 Overview

CVE-2024-23938 is a stack-based buffer overflow in the Silicon Labs Gecko OS debug interface. The flaw allows network-adjacent attackers to execute arbitrary code on affected devices without authentication. The debug interface fails to validate the length of user-supplied data before copying it to a stack-based buffer. Successful exploitation grants attackers code execution in the context of the device. The vulnerability was originally tracked by the Zero Day Initiative as ZDI-CAN-23184 and published as ZDI-24-868. It is classified under CWE-121 (Stack-based Buffer Overflow) and CWE-787 (Out-of-bounds Write).

Critical Impact
Unauthenticated attackers on an adjacent network can achieve arbitrary code execution on Gecko OS devices through malformed debug interface traffic.

Affected Products

Silicon Labs Gecko OS version 1.0.46
Devices exposing the Gecko OS debug interface on adjacent networks
Embedded and IoT deployments running the affected firmware build

Discovery Timeline

2024-09-28 - CVE-2024-23938 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2024-23938

Vulnerability Analysis

The vulnerability resides in the Gecko OS debug interface. The interface accepts data from adjacent-network clients without enforcing a bounded length before copying it into a fixed-size stack buffer. An attacker who reaches the debug service can send an oversized payload that overwrites adjacent stack memory, including the saved return address. Because authentication is not required, any device that exposes the debug interface on a reachable link-local segment is at risk. The Zero Day Initiative advisory ZDI-24-868 documents the disclosure through its coordinated program.

Root Cause

The root cause is missing input length validation in the debug interface's message handling path. The service performs an unsafe copy of attacker-controlled bytes into a stack buffer, mapping to CWE-121 (Stack-based Buffer Overflow) and CWE-787 (Out-of-bounds Write). No bounds check separates network input from the destination buffer.

Attack Vector

Exploitation requires network-adjacent access, such as the same Wi-Fi network, VLAN, or link-local segment as the target device. The attacker sends a crafted message to the debug interface containing a payload larger than the receiving buffer. The overflow corrupts stack metadata and can be shaped to divert execution to attacker-controlled code. No user interaction or credentials are needed.

No public proof-of-concept code has been released. Refer to the Zero Day Initiative Advisory ZDI-24-868 and the Silicon Labs Community Post for vendor-authoritative technical detail.

Detection Methods for CVE-2024-23938

Indicators of Compromise

Unexpected inbound connections to Gecko OS debug interface ports from unknown adjacent-network hosts.
Device crashes, unexpected reboots, or watchdog resets on Gecko OS endpoints that coincide with abnormal debug traffic.
Anomalous outbound connections from embedded devices after receiving malformed debug frames.

Detection Strategies

Inspect layer-2 and layer-3 traffic destined for Gecko OS devices for oversized or malformed debug interface messages.
Baseline expected debug interface usage and alert on any access originating from non-administrative hosts.
Correlate device availability failures with adjacent-network traffic patterns to identify probing attempts.

Monitoring Recommendations

Enable wireless intrusion detection on segments hosting Gecko OS devices to flag anomalous link-local traffic.
Capture and retain packet metadata for the debug interface to support post-incident forensics.
Monitor firmware version inventories to confirm all Gecko OS devices are tracked against 1.0.46 exposure.

How to Mitigate CVE-2024-23938

Immediate Actions Required

Disable the Gecko OS debug interface on production devices where it is not operationally required.
Restrict the network segments where Gecko OS devices reside to trusted administrative hosts only.
Apply firmware updates from Silicon Labs as documented in the Silicon Labs Community Post.

Patch Information

Silicon Labs published guidance through its community advisory. Consult the Silicon Labs Community Post for the fixed release and upgrade procedure applicable to your device family. The Zero Day Initiative tracks the coordinated disclosure under advisory ZDI-24-868.

Workarounds

Segment Gecko OS devices onto isolated VLANs or wireless SSIDs that block traffic from untrusted clients.
Configure firewalls and access points to drop inbound traffic to the debug interface from non-management sources.
Where the debug interface must remain enabled, permit access only from a hardened jump host on the same segment.

bash

# Example: block inbound access to the Gecko OS debug interface at a gateway
# Replace <DEBUG_PORT> and <DEVICE_SUBNET> with values from vendor documentation
iptables -A FORWARD -p tcp --dport <DEBUG_PORT> -d <DEVICE_SUBNET> -j DROP
iptables -A FORWARD -p udp --dport <DEBUG_PORT> -d <DEVICE_SUBNET> -j DROP