CVE-2026-5992: Tenda F451 Buffer Overflow Vulnerability

CVE-2026-5992 Overview

A stack-based buffer overflow vulnerability has been identified in Tenda F451 firmware version 1.0.0.7. The vulnerability exists in the fromP2pListFilter function within the /goform/P2pListFilter endpoint. By manipulating the page argument, an attacker can trigger a stack-based buffer overflow condition. This vulnerability can be exploited remotely over the network and proof-of-concept exploit code has been publicly disclosed, increasing the risk of active exploitation attempts.

Critical Impact

Remote attackers can exploit this stack-based buffer overflow to potentially execute arbitrary code, compromise device integrity, or cause denial of service conditions on affected Tenda F451 routers.

Affected Products

• Tenda F451 firmware version 1.0.0.7
• Tenda F451 devices with vulnerable /goform/P2pListFilter endpoint

Discovery Timeline

• April 10, 2026 - CVE-2026-5992 published to NVD
• April 13, 2026 - Last updated in NVD database

Technical Details for CVE-2026-5992

Vulnerability Analysis

This vulnerability is classified under CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer), which represents a fundamental memory safety issue in the affected firmware. The vulnerable function fromP2pListFilter fails to properly validate the length of user-supplied input before copying it to a fixed-size stack buffer.

The network-accessible nature of this vulnerability significantly increases its exploitability, as attackers do not require local access to the device. Authentication requirements exist but do not substantially mitigate the risk given the typical deployment of consumer routers and the potential for credential compromise or default credential usage.

When the page parameter receives input exceeding the expected buffer size, the overflow corrupts adjacent stack memory, potentially overwriting return addresses or other critical control structures. Successful exploitation could allow attackers to achieve arbitrary code execution with the privileges of the web server process on the router.

Root Cause

The root cause is insufficient bounds checking in the fromP2pListFilter function when processing the page argument from HTTP requests to /goform/P2pListFilter. The function copies user-controlled data to a stack-allocated buffer without verifying that the input length does not exceed the buffer's capacity, leading to a classic stack-based buffer overflow condition.

Attack Vector

The attack vector is network-based, targeting the web management interface of the Tenda F451 router. An authenticated attacker can craft a malicious HTTP request to the /goform/P2pListFilter endpoint with an oversized page parameter value. The exploitation technique involves:

1. Identifying a vulnerable Tenda F451 device accessible over the network
2. Authenticating to the device's web interface (or leveraging default credentials)
3. Sending a crafted request to /goform/P2pListFilter with a malicious page parameter
4. Overflowing the stack buffer to corrupt control flow data
5. Potentially achieving code execution or causing device instability

The public disclosure of this vulnerability means exploit code is available, making it accessible to less sophisticated attackers. Technical details can be found in the GitHub security research issue and the VulDB entry.

Detection Methods for CVE-2026-5992

Indicators of Compromise

• Unusual HTTP POST requests to /goform/P2pListFilter with abnormally large page parameter values
• Router crashes, reboots, or unexpected behavior following web interface access
• Anomalous outbound network connections originating from the router
• Modified router configuration or firmware without administrator action

Detection Strategies

• Implement network intrusion detection rules monitoring for oversized parameters in requests to Tenda router endpoints
• Monitor for HTTP requests to /goform/P2pListFilter containing page parameters exceeding normal length thresholds
• Deploy anomaly detection for web traffic destined to router management interfaces
• Configure logging on network perimeter devices to capture requests to known vulnerable endpoints

Monitoring Recommendations

• Enable verbose logging on the Tenda F451 web interface if available
• Monitor network traffic for exploitation patterns targeting the /goform/P2pListFilter endpoint
• Implement alerting for router instability or unexpected reboots that may indicate exploitation attempts
• Review router access logs for authentication attempts from unexpected IP addresses

How to Mitigate CVE-2026-5992

Immediate Actions Required

• Restrict network access to the router's web management interface to trusted IP addresses only
• Disable remote management features if not required for operations
• Change default credentials on all Tenda F451 devices
• Segment IoT and network infrastructure devices from general network traffic
• Monitor the Tenda official website for firmware updates addressing this vulnerability

Patch Information

At the time of this publication, no vendor patch has been confirmed. Administrators should monitor Tenda's official channels for security updates addressing CVE-2026-5992. The vulnerability affects Tenda F451 firmware version 1.0.0.7. Check the VulDB vulnerability entry for updated patch status and additional technical intelligence.

Workarounds

• Implement firewall rules to block external access to the router's management interface (typically port 80/443)
• Use VPN or out-of-band management for remote administration rather than exposing the web interface
• Consider deploying a network-level web application firewall to filter malicious requests targeting vulnerable endpoints
• If the device is not critical, consider replacing it with a router from a vendor with better security update practices

# Example iptables rule to restrict management interface access
# Allow management access only from trusted admin subnet
iptables -A INPUT -p tcp --dport 80 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -s 192.168.1.0/24 -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP