CVE-2026-3271: Tenda F453 Buffer Overflow Vulnerability

CVE-2026-3271 Overview

CVE-2026-3271 is a buffer overflow vulnerability in the Tenda F453 router running firmware version 1.0.0.3. The flaw resides in the fromP2pListFilter function within the /goform/P2pListFilter endpoint handled by the httpd component. Attackers manipulate the page argument to trigger memory corruption. The issue is exploitable remotely over the network and a public exploit description has been released. The vulnerability maps to CWE-119 and CWE-120, covering improper restriction of operations within memory bounds and classic buffer copy without size checking.

Critical Impact

Remote attackers can corrupt memory in the Tenda F453 web server, potentially leading to arbitrary code execution or denial of service on the affected router.

Affected Products

• Tenda F453 router (hardware)
• Tenda F453 firmware version 1.0.0.3
• Deployments exposing the httpd web management interface

Discovery Timeline

• 2026-02-27 - CVE-2026-3271 published to NVD
• 2026-02-27 - Last updated in NVD database

Technical Details for CVE-2026-3271

Vulnerability Analysis

The vulnerability exists in the fromP2pListFilter handler exposed through the /goform/P2pListFilter URI of the embedded httpd daemon. The handler accepts an HTTP page parameter and copies the supplied value into a fixed-size buffer without validating its length. When the input exceeds the destination buffer, adjacent stack or heap memory is overwritten. This results in classic buffer overflow conditions consistent with CWE-120. Successful exploitation can corrupt control data such as saved return addresses, enabling code execution under the privileges of the httpd process. Authentication is required at a low privilege level, but no user interaction is needed.

Root Cause

The root cause is missing bounds enforcement on the page argument before it is processed by fromP2pListFilter. The Tenda firmware uses unsafe memory copy patterns common in MIPS-based SOHO routers, where attacker-controlled query parameters are written into stack buffers without length validation. This pattern matches CWE-119, improper restriction of operations within the bounds of a memory buffer.

Attack Vector

An attacker reaches the vulnerable endpoint over the network by sending a crafted HTTP request to /goform/P2pListFilter with an oversized page parameter. Because the management interface is often exposed on the LAN and sometimes on the WAN, the attack surface includes both internal threat actors and remote attackers when remote administration is enabled. Refer to the GitHub vulnerability documentation and VulDB entry #347995 for technical reproduction details. No verified exploit code is reproduced here.

Detection Methods for CVE-2026-3271

Indicators of Compromise

• HTTP requests to /goform/P2pListFilter containing abnormally long page parameter values.
• Unexpected restarts or crashes of the httpd process on the Tenda F453.
• Outbound connections from the router to unknown hosts following suspicious management-plane traffic.

Detection Strategies

• Inspect web server logs and network captures for POST or GET requests targeting /goform/P2pListFilter with parameter lengths exceeding expected ranges.
• Deploy network IDS signatures that flag oversized page query strings directed at Tenda management endpoints.
• Correlate router reboot events with preceding HTTP requests to the management interface.

Monitoring Recommendations

• Monitor administrative interfaces of SOHO routers for unauthorized access attempts and anomalous request sizes.
• Track firmware versions across the device inventory and alert on hosts still running Tenda F453 1.0.0.3.
• Capture syslog or remote logging from the router to detect repeated httpd failures.

How to Mitigate CVE-2026-3271

Immediate Actions Required

• Restrict access to the router web management interface to trusted management VLANs only.
• Disable remote WAN-side administration on the Tenda F453 until a patched firmware is available.
• Rotate administrator credentials, since exploitation requires low-privileged authentication.

Patch Information

No vendor patch has been published in the referenced advisories at the time of disclosure. Monitor the Tenda official website for firmware updates addressing the fromP2pListFilter buffer overflow. Until a fixed firmware is released, treat the device as exposed and apply compensating network controls.

Workarounds

• Place the Tenda F453 behind a firewall that blocks untrusted access to TCP ports used by httpd.
• Apply ACLs to permit management traffic only from specific administrator IP addresses.
• Consider replacing end-of-support SOHO devices that no longer receive timely firmware updates.

# Example: restrict access to the Tenda F453 management interface using iptables on an upstream gateway
iptables -A FORWARD -p tcp -d <ROUTER_IP> --dport 80 -s <ADMIN_SUBNET> -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 <ADMIN_SUBNET> -j ACCEPT
iptables -A FORWARD -p tcp -d <ROUTER_IP> --dport 443 -j DROP