CVE-2026-3697: Planet ICG-2510 Buffer Overflow Flaw

CVE-2026-3697 Overview

A stack-based buffer overflow vulnerability has been identified in Planet ICG-2510 firmware version 1.0_20250811. The vulnerability exists in the sub_40C8E4 function within the /usr/sbin/httpd binary, specifically in the Language Package Configuration Handler component. By manipulating the Language argument, an authenticated attacker can trigger a stack-based buffer overflow condition that may lead to denial of service or potential code execution on the affected device.

Critical Impact

Remote attackers with low privileges can exploit this vulnerability to corrupt stack memory, potentially leading to system instability, denial of service, or arbitrary code execution on the affected IoT gateway device.

Affected Products

• Planet ICG-2510 firmware version 1.0_20250811
• Planet ICG-2510 Language Package Configuration Handler component
• /usr/sbin/httpd web server binary on Planet ICG-2510 devices

Discovery Timeline

• 2026-03-08 - CVE-2026-3697 published to NVD
• 2026-03-09 - Last updated in NVD database

Technical Details for CVE-2026-3697

Vulnerability Analysis

This vulnerability is classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer), indicating that the affected function fails to properly validate the bounds of input data before performing memory operations. The vulnerability resides in the embedded web server (httpd) that handles Language Package Configuration requests on the Planet ICG-2510 gateway device.

When processing language configuration parameters, the sub_40C8E4 function does not adequately validate the length or content of the Language argument before copying it to a stack-allocated buffer. This allows an attacker to supply an oversized or specially crafted input that overflows the buffer boundaries, corrupting adjacent stack memory including potential return addresses or saved registers.

The vendor was contacted regarding this disclosure but did not respond, leaving no official patch or mitigation guidance available at this time.

Root Cause

The root cause of this vulnerability is the lack of proper input validation and boundary checking in the sub_40C8E4 function when handling the Language parameter. The function appears to copy user-controlled data to a fixed-size stack buffer without verifying that the input length does not exceed the allocated buffer size. This classic buffer overflow condition allows attackers to write beyond the intended memory boundaries.

Attack Vector

The attack can be launched remotely over the network against the Planet ICG-2510 web management interface. An attacker with low-privilege access to the device's web interface can craft a malicious HTTP request to the Language Package Configuration Handler, supplying an oversized or malformed Language parameter value. When the vulnerable sub_40C8E4 function processes this input, it copies the data to a stack buffer without proper length validation, resulting in stack memory corruption.

The attacker can leverage this overflow to overwrite critical stack data such as saved return addresses, potentially redirecting program execution flow. Given the embedded nature of the device and typical lack of modern exploit mitigations on IoT firmware, successful exploitation could lead to arbitrary code execution with the privileges of the httpd process.

Detection Methods for CVE-2026-3697

Indicators of Compromise

• Unusual HTTP requests to the Language Package Configuration Handler endpoint with abnormally long Language parameter values
• Unexpected crashes or restarts of the httpd service on Planet ICG-2510 devices
• Anomalous network traffic patterns targeting the web management interface of ICG-2510 gateways
• Evidence of exploitation attempts in device logs showing malformed configuration requests

Detection Strategies

• Implement network intrusion detection rules to identify HTTP requests with oversized Language parameters targeting ICG-2510 devices
• Monitor for repeated connection attempts to the web management interface followed by service interruptions
• Deploy endpoint detection solutions capable of identifying buffer overflow exploitation patterns on embedded devices
• Configure alerting for any unexpected process crashes on the ICG-2510 gateway devices

Monitoring Recommendations

• Enable comprehensive logging on Planet ICG-2510 devices and forward logs to a centralized SIEM for analysis
• Implement network segmentation to isolate IoT gateway devices and limit exposure of management interfaces
• Establish baseline behavior for web interface access patterns and alert on deviations
• Conduct regular vulnerability scans of network infrastructure devices including IoT gateways

How to Mitigate CVE-2026-3697

Immediate Actions Required

• Restrict network access to the Planet ICG-2510 web management interface to trusted administrative IP addresses only
• Implement firewall rules to block external access to the device's HTTP management port
• Place affected devices behind a VPN or jump host requiring additional authentication
• Monitor affected devices closely for signs of exploitation or unusual behavior
• Consider temporarily disabling the web management interface if not required for operations

Patch Information

No official patch is currently available from the vendor. According to the vulnerability disclosure, the vendor was contacted regarding this issue but did not respond. Organizations using affected Planet ICG-2510 devices should monitor for firmware updates and apply patches as soon as they become available. Additional technical details can be found in the GitHub IoT Vulnerability Report and VulDB #349643.

Workarounds

• Implement strict network access controls to limit which hosts can reach the device's web management interface
• Use a web application firewall (WAF) to filter requests with excessively long Language parameters
• Disable the web management interface entirely and manage the device through alternative methods if available
• Isolate affected devices on a dedicated management VLAN with restricted access
• Consider replacing vulnerable devices with alternative products that receive active security support