CVE-2024-23973: Silabs Gecko OS RCE Vulnerability

CVE-2024-23973 Overview

CVE-2024-23973 is a stack-based buffer overflow [CWE-120] in Silicon Labs Gecko OS. The flaw exists in the handling of HTTP GET requests, where the service copies user-supplied data into a fixed-size stack buffer without validating its length. Network-adjacent attackers can exploit the issue without authentication to execute arbitrary code in the context of the device firmware.

Gecko OS is an embedded operating system used on Silicon Labs wireless connectivity modules, so successful exploitation directly affects IoT and embedded deployments that expose the HTTP interface on adjacent networks.

Critical Impact
Unauthenticated adjacent-network attackers can achieve arbitrary code execution on affected Silicon Labs Gecko OS devices via a crafted HTTP GET request.

Affected Products

Silicon Labs Gecko OS (all versions per vendor advisory)
Wireless modules and IoT devices running vulnerable Gecko OS firmware
Embedded deployments exposing the Gecko OS HTTP server on adjacent networks

Discovery Timeline

2025-01-31 - CVE-2024-23973 published to the National Vulnerability Database (NVD)
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2024-23973

Vulnerability Analysis

The vulnerability resides in the HTTP GET request handler of Silicon Labs Gecko OS. When the service processes an incoming GET request, it copies attacker-controlled data from the request into a stack-allocated buffer. The routine does not verify that the source length fits within the destination buffer, producing a classic stack-based buffer overflow.

Exploitation requires only network adjacency, not authentication or user interaction. On embedded devices, stack overflows commonly overwrite the saved return address or adjacent control data, enabling attackers to redirect execution flow. Because Gecko OS runs on microcontroller-class hardware, exploit primitives depend on the device's memory protection features and any stack protection provided by the firmware build.

Successful exploitation yields code execution in the context of the firmware itself, giving the attacker full control over device functionality, connected sensors, and any credentials or keys stored on the module.

Root Cause

The root cause is missing length validation before a copy operation into a fixed-size stack buffer, categorized under [CWE-120] Buffer Copy without Checking Size of Input. The HTTP parser trusts the size of user-supplied fields in a GET request and copies them into local storage without bounds checking.

Attack Vector

The attack vector is Adjacent Network, meaning the attacker must reside on the same logical network segment as the target device, such as the same Wi-Fi network or broadcast domain. The attacker sends a crafted HTTP GET request whose parsed fields exceed the expected size, triggering the overflow inside the HTTP handler.

No verified public proof-of-concept exploit code is available. Technical details are documented in the Zero Day Initiative Advisory ZDI-24-873 and the associated Silicon Labs Community Post.

Detection Methods for CVE-2024-23973

Indicators of Compromise

HTTP GET requests to Gecko OS devices containing abnormally long URIs, headers, or query parameters that exceed typical embedded HTTP field sizes.
Unexpected reboots, watchdog resets, or crash loops on Silicon Labs modules following inbound HTTP traffic.
Outbound network connections initiated by IoT devices to unfamiliar hosts after HTTP interaction.

Detection Strategies

Inspect network traffic destined for Gecko OS HTTP endpoints and flag GET requests whose header or URI lengths exceed device-appropriate thresholds.
Correlate device crash telemetry with preceding inbound HTTP sessions to identify probable exploitation attempts.
Baseline normal HTTP traffic patterns to affected devices and alert on deviations in request size, frequency, or source.

Monitoring Recommendations

Enable logging on network segments where Silicon Labs modules operate and forward logs to a centralized analytics platform.
Monitor device availability and firmware integrity to detect post-exploitation persistence or tampering.
Track lateral movement attempts from network segments containing IoT devices toward higher-value assets.

How to Mitigate CVE-2024-23973

Immediate Actions Required

Inventory all deployed Silicon Labs Gecko OS devices and identify those exposing the HTTP interface.
Restrict network access to Gecko OS HTTP endpoints using VLAN segmentation, firewall rules, or wireless isolation.
Disable the HTTP server on affected devices where the interface is not operationally required.
Apply firmware updates from Silicon Labs as soon as they are available for your specific module.

Patch Information

Refer to the Silicon Labs Community Post for vendor guidance and firmware update availability. The Zero Day Initiative Advisory ZDI-24-873 provides additional advisory details. Because Gecko OS runs on many downstream products, verify with the device integrator whether an updated firmware image is available for your hardware revision.

Workarounds

Place affected devices on isolated network segments accessible only to trusted management hosts.
Enforce wireless client isolation on Wi-Fi networks hosting Gecko OS modules to block adjacent-network reachability between clients.
Terminate or proxy HTTP administration through a hardened gateway that validates request sizes before forwarding.
Disable remote management features on the module when they are not actively used.

bash

# Example firewall rule restricting HTTP access to Gecko OS devices
# Replace 10.10.20.0/24 with the IoT segment and 10.10.99.10 with the management host
iptables -A FORWARD -p tcp -d 10.10.20.0/24 --dport 80 -s 10.10.99.10 -j ACCEPT
iptables -A FORWARD -p tcp -d 10.10.20.0/24 --dport 80 -j DROP