CVE-2026-5841: Tenda i3 Path Traversal Vulnerability

CVE-2026-5841 Overview

A path traversal vulnerability has been identified in the Tenda i3 router firmware version 1.0.0.6(2204). The affected element is the R7WebsSecurityHandler function within the HTTP Handler component. By manipulating input parameters, an attacker can traverse the file system to access unauthorized files and directories. This vulnerability is remotely exploitable and a proof-of-concept exploit has been made publicly available.

Critical Impact

Remote attackers can exploit this path traversal vulnerability to access sensitive files on the device, potentially exposing configuration data, credentials, or other critical system information without authentication.

Affected Products

• Tenda i3 Firmware Version 1.0.0.6(2204)
• Tenda i3 devices with affected HTTP Handler component
• Network infrastructure utilizing vulnerable Tenda i3 routers

Discovery Timeline

• 2026-04-09 - CVE-2026-5841 published to NVD
• 2026-04-09 - Last updated in NVD database

Technical Details for CVE-2026-5841

Vulnerability Analysis

This vulnerability is classified as CWE-22 (Improper Limitation of a Pathname to a Restricted Directory), commonly known as path traversal or directory traversal. The R7WebsSecurityHandler function in the Tenda i3 router's HTTP Handler fails to properly sanitize user-supplied input before using it in file system operations.

When processing HTTP requests, the handler does not adequately validate path components, allowing attackers to include directory traversal sequences (such as ../) in their requests. This enables unauthorized access to files and directories outside the intended web root, potentially exposing sensitive system files, configuration data, and credentials stored on the device.

The network-accessible nature of the vulnerability means that any attacker with network access to the affected device can exploit this flaw without requiring authentication or user interaction.

Root Cause

The root cause of this vulnerability lies in the insufficient input validation within the R7WebsSecurityHandler function. The HTTP Handler component fails to properly sanitize path parameters, allowing directory traversal sequences to bypass security controls. This implementation flaw enables attackers to escape the intended directory structure and access arbitrary files on the file system.

Attack Vector

The attack can be executed remotely over the network. An attacker sends specially crafted HTTP requests to the vulnerable Tenda i3 device containing path traversal sequences. These malicious requests target the R7WebsSecurityHandler function, which processes them without adequate validation. The traversal sequences allow the attacker to navigate outside the web root directory and access sensitive files.

The vulnerability mechanism involves sending HTTP requests with path manipulation sequences through the HTTP Handler component. The R7WebsSecurityHandler function processes these requests without properly filtering directory traversal patterns, enabling file system access beyond intended boundaries. For detailed technical analysis and proof-of-concept information, refer to the GitHub PoC Repository.

Detection Methods for CVE-2026-5841

Indicators of Compromise

• HTTP requests to Tenda i3 devices containing path traversal sequences such as ../ or encoded variants (%2e%2e%2f)
• Unusual access patterns to system files through the HTTP interface
• Log entries showing requests attempting to access files outside the web root directory
• Unexpected file read operations from the R7WebsSecurityHandler function

Detection Strategies

• Implement network intrusion detection rules to identify HTTP requests containing path traversal patterns targeting Tenda devices
• Monitor web server logs for suspicious requests with ../ sequences or URL-encoded directory traversal attempts
• Deploy web application firewall (WAF) rules to block requests containing common path traversal payloads
• Utilize SentinelOne Singularity™ to monitor network traffic and detect exploitation attempts against IoT devices

Monitoring Recommendations

• Configure centralized logging for all Tenda i3 device access and monitor for anomalous patterns
• Set up alerts for HTTP requests to IoT devices that contain path manipulation sequences
• Implement network segmentation to limit exposure of vulnerable devices and enhance monitoring capabilities
• Review access logs regularly for evidence of directory traversal exploitation attempts

How to Mitigate CVE-2026-5841

Immediate Actions Required

• Isolate affected Tenda i3 devices from untrusted networks until a patch is available
• Implement network access controls to restrict who can reach the device's HTTP interface
• Deploy a web application firewall or reverse proxy with path traversal filtering in front of affected devices
• Monitor for and block exploitation attempts using network security tools

Patch Information

No official vendor patch information is currently available for this vulnerability. Organizations should monitor the Tenda Official Website for security updates and firmware releases. Check the VulDB entry regularly for updated remediation guidance.

Workarounds

• Restrict network access to the Tenda i3 management interface using firewall rules or network segmentation
• Place vulnerable devices behind a reverse proxy that sanitizes and filters path traversal sequences
• Disable remote management features if not required for operational purposes
• Consider replacing affected devices with alternative products if no patch becomes available in a reasonable timeframe

Network segmentation configuration can limit exposure by restricting access to the vulnerable device's HTTP interface to only trusted management networks. This reduces the attack surface while awaiting an official vendor patch.