CVE-2026-67965 Overview
CVE-2026-67965 is a command injection vulnerability affecting Tenda W20E router firmware version 16.01.0.6(2782). The flaw resides in the url_need_login function and allows a remote, unauthenticated attacker to execute arbitrary code on the device. The weakness is categorized under [CWE-78], improper neutralization of special elements used in an OS command. Successful exploitation grants attacker-controlled command execution on the router, undermining confidentiality, integrity, and availability of the device and the network segment behind it.
Critical Impact
Unauthenticated remote attackers can execute arbitrary operating system commands on affected Tenda W20E devices over the network, enabling full device takeover.
Affected Products
- Tenda W20E router firmware version 16.01.0.6(2782)
Discovery Timeline
- 2026-08-17 - CVE-2026-67965 published to the National Vulnerability Database (NVD)
- 2026-08-18 - Last updated in NVD database
Technical Details for CVE-2026-67965
Vulnerability Analysis
The vulnerability is a network-reachable OS command injection in the Tenda W20E web management interface. The url_need_login function processes attacker-supplied input without adequate sanitization before passing it to a system command handler. An attacker can send a crafted HTTP request to the router and coerce the underlying shell to execute injected commands. Because the vulnerable code path is reachable prior to authentication, exploitation requires no valid credentials and no user interaction. Successful exploitation runs the injected commands in the context of the router firmware, typically with elevated privileges on embedded Linux devices.
Root Cause
The root cause is improper neutralization of special elements used in an OS command [CWE-78]. The url_need_login handler consumes untrusted request data and incorporates it into a command string that is executed by the device's shell. Missing input validation and lack of safe command-construction primitives, such as argument arrays or strict allowlists, permit shell metacharacters to break out of the intended context.
Attack Vector
Exploitation is performed remotely over the network against the router's HTTP management service. An attacker crafts a request that reaches the url_need_login code path and embeds shell metacharacters or command separators in a parameter processed by the function. When the router evaluates the request, the injected payload is executed by the underlying operating system. Devices exposing the management interface to the internet or to untrusted network segments are at highest risk. According to the current Exploit Prediction Scoring System data, no public exploit has been confirmed available at the time of publication, but a public vulnerability disclosure repository referenced by NVD contains technical details.
Refer to the GitHub Vulnerability Disclosure for reported technical specifics. No verified proof-of-concept code is reproduced here.
Detection Methods for CVE-2026-67965
Indicators of Compromise
- Unexpected outbound connections from the router to unfamiliar IP addresses, particularly on non-standard ports.
- Presence of shell metacharacters such as ;, |, &&, or backticks in HTTP request parameters targeting the router's management interface.
- Unauthorized configuration changes, new user accounts, or modified firewall and DNS settings on the device.
- Unexpected processes or persistence artifacts in device logs referencing invocations of /bin/sh or busybox triggered by web requests.
Detection Strategies
- Inspect HTTP requests to the router management interface for anomalous parameters targeting authentication or login-check endpoints associated with url_need_login.
- Correlate inbound web-management traffic with subsequent outbound connections from the router to identify command-and-control behavior.
- Alert on any exposure of the router's administrative interface to WAN or untrusted networks.
Monitoring Recommendations
- Continuously monitor network traffic to and from perimeter routers using an IDS or NDR sensor tuned for command-injection payloads.
- Log and review DNS queries originating from network infrastructure devices to detect beaconing.
- Maintain an inventory of firmware versions on all Tenda devices and alert on drift from approved baselines.
How to Mitigate CVE-2026-67965
Immediate Actions Required
- Restrict access to the Tenda W20E management interface to trusted management VLANs and disable WAN-side administration.
- Place affected devices behind a network segmentation boundary and block untrusted HTTP and HTTPS traffic to the router's management ports.
- Rotate administrative credentials and audit device configuration for unauthorized modifications.
- Track the vendor advisory channel for a firmware update addressing the url_need_login function.
Patch Information
No vendor patch or fixed firmware version is listed in the NVD entry at the time of publication. Consult the GitHub Vulnerability Disclosure and Tenda support channels for updates. Apply firmware updates as soon as the vendor releases a corrected build.
Workarounds
- Disable remote web management on the WAN interface and permit management only from a dedicated internal subnet.
- Enforce strict access control lists on upstream firewalls to block untrusted sources from reaching the router's management ports.
- Replace end-of-life or unpatchable devices with supported hardware where a fix is not available.
# Example: restrict router web management to a trusted subnet on an upstream firewall
iptables -A FORWARD -p tcp -d <router_ip> --dport 80 -s 10.10.10.0/24 -j ACCEPT
iptables -A FORWARD -p tcp -d <router_ip> --dport 80 -j DROP
iptables -A FORWARD -p tcp -d <router_ip> --dport 443 -s 10.10.10.0/24 -j ACCEPT
iptables -A FORWARD -p tcp -d <router_ip> --dport 443 -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
