CVE-2026-5841 Overview
CVE-2026-5841 is a path traversal vulnerability [CWE-22] affecting the Tenda i3 wireless access point running firmware version 1.0.0.6(2204). The flaw resides in the R7WebsSecurityHandler function within the device's HTTP handler component. Attackers can manipulate request input to traverse outside the intended directory and access restricted resources. The vulnerability is remotely exploitable over the network without authentication. Public exploit details have been published, increasing the likelihood of opportunistic abuse against exposed devices.
Critical Impact
Unauthenticated remote attackers can traverse the file system on affected Tenda i3 devices through the HTTP handler, exposing sensitive configuration and potentially enabling authentication bypass.
Affected Products
- Tenda i3 hardware appliance
- Tenda i3 firmware version 1.0.0.6(2204)
- HTTP Handler component using the R7WebsSecurityHandler function
Discovery Timeline
- 2026-04-09 - CVE-2026-5841 published to NVD
- 2026-04-30 - Last updated in NVD database
Technical Details for CVE-2026-5841
Vulnerability Analysis
The vulnerability stems from improper sanitization of path components processed by the R7WebsSecurityHandler function in the Tenda i3 HTTP service. The handler is responsible for evaluating request URIs against the device's security checks. Because the function does not normalize traversal sequences such as ../ before resolving the requested resource, attackers can escape the intended web root.
This weakness is classified under [CWE-22], Improper Limitation of a Pathname to a Restricted Directory. Public references on VulDB (#356297) and a GitHub PoC Repository describe the issue as enabling authentication bypass via path manipulation. The EPSS probability for near-term exploitation is currently low, but public disclosure of proof-of-concept material raises the operational risk for internet-exposed devices.
Root Cause
The root cause is insufficient input validation in R7WebsSecurityHandler. The function compares request paths against an allowlist of unauthenticated endpoints without canonicalizing the supplied URI. Attackers can submit crafted strings containing directory traversal characters to make a protected endpoint appear unauthenticated, or to read files outside the intended directory.
Attack Vector
The attack vector is network-based and requires no authentication or user interaction. An attacker sends an HTTP request to the device management interface containing traversal sequences embedded in the URI. The vulnerable handler resolves the manipulated path and either bypasses the authentication check or returns content from outside the web root. Devices exposing their management interface to untrusted networks are at highest risk.
No verified exploit code is reproduced here. Technical details and a public proof-of-concept are available in the referenced GitHub PoC Repository and the VulDB #356297 entry.
Detection Methods for CVE-2026-5841
Indicators of Compromise
- HTTP requests to the device management interface containing ../ or URL-encoded variants such as %2e%2e%2f in the URI path
- Access log entries showing successful responses to paths that normally require authentication
- Unexpected outbound connections from the device or new administrative sessions originating from untrusted IP addresses
Detection Strategies
- Inspect web server and network logs for traversal patterns targeting endpoints handled by R7WebsSecurityHandler
- Deploy network IDS/IPS signatures that flag directory traversal sequences against Tenda HTTP management ports
- Correlate authentication events with URI patterns to identify requests that succeeded despite missing credentials
Monitoring Recommendations
- Continuously monitor management plane traffic to embedded network devices and alert on anomalous URI structures
- Track configuration changes and administrative logins on Tenda i3 devices and investigate any activity from unrecognized sources
- Ingest network device logs into a centralized analytics platform to enable retroactive hunting for traversal indicators
How to Mitigate CVE-2026-5841
Immediate Actions Required
- Restrict the Tenda i3 web management interface to trusted management VLANs and block exposure to the public internet
- Enforce network segmentation between user networks and access point management interfaces
- Audit existing devices for unauthorized administrative changes that may indicate prior exploitation
Patch Information
No vendor advisory or fixed firmware version is listed in the published references at the time of writing. Consult the Tenda Official Website for firmware updates addressing CVE-2026-5841 and apply any released patches for the i3 product line as soon as they become available.
Workarounds
- Disable remote HTTP management on Tenda i3 devices where it is not strictly required
- Place affected devices behind a firewall that filters inbound traffic to management ports and inspects URIs for traversal sequences
- Rotate administrative credentials and review device configurations after restricting network access
# Example: restrict access to the Tenda i3 management interface to a trusted subnet
# (replace 10.10.0.0/24 with your management network)
iptables -A INPUT -p tcp --dport 80 -s 10.10.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -s 10.10.0.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
