CVE-2026-7219 Overview
CVE-2026-7219 is a buffer overflow vulnerability in the Totolink N300RT router running firmware version 3.4.0-B20250430. The flaw resides in an unknown function of the /boafrm/formIpQoS endpoint, where manipulation of the entry_name argument triggers memory corruption. Attackers can exploit the vulnerability remotely over the network. A public proof-of-concept has been published, increasing the risk of opportunistic exploitation against exposed devices. The weakness is classified under CWE-119, covering improper restriction of operations within the bounds of a memory buffer.
Critical Impact
Remote attackers with valid privileges can corrupt memory on affected Totolink N300RT routers, potentially leading to denial of service or arbitrary code execution on the device.
Affected Products
- Totolink N300RT router
- Firmware version 3.4.0-B20250430
- /boafrm/formIpQoS web interface handler
Discovery Timeline
- 2026-04-28 - CVE-2026-7219 published to the National Vulnerability Database (NVD)
- 2026-04-28 - Last updated in NVD database
Technical Details for CVE-2026-7219
Vulnerability Analysis
The vulnerability exists in the request handler for /boafrm/formIpQoS within the boa web server embedded in the Totolink N300RT firmware. When the handler processes the entry_name HTTP parameter, it copies user-controlled data into a fixed-size memory buffer without validating the input length. The resulting buffer overflow corrupts adjacent memory regions on the device.
Because the boa web server runs with elevated privileges on the router, successful exploitation can compromise the integrity, confidentiality, and availability of the device. Reported impact includes high impact to all three properties on the vulnerable component, while no impact extends beyond the device scope.
A proof-of-concept exploit has been published to a public GitHub PoC Repository, and the issue is tracked in the VulDB Vulnerability Report.
Root Cause
The root cause is the absence of input length validation on the entry_name parameter before it is written into a stack or heap buffer. This is a classic CWE-119 memory safety failure common to embedded C web handlers in consumer routers.
Attack Vector
The attack is delivered over the network by sending a crafted HTTP request to the /boafrm/formIpQoS endpoint with an oversized entry_name value. Exploitation requires authenticated access to the router's management interface, as indicated by the high privileges required in the CVSS vector. Routers with management exposed to the WAN or with default or weak credentials face the greatest risk.
The vulnerability is described in prose only because no verified exploit code is reproduced here. See the GitHub PoC Repository for technical details.
Detection Methods for CVE-2026-7219
Indicators of Compromise
- HTTP POST requests to /boafrm/formIpQoS containing unusually long entry_name values
- Unexpected reboots, crashes, or restarts of the boa web server process on the router
- Outbound connections from the router to unknown hosts following administrative HTTP traffic
- Configuration changes to QoS, DNS, or firewall rules without a corresponding administrator action
Detection Strategies
- Inspect web server logs on the router for requests targeting /boafrm/formIpQoS with anomalous parameter sizes
- Deploy network intrusion detection signatures that flag HTTP requests containing oversized entry_name fields directed at Totolink management interfaces
- Correlate management-plane HTTP activity with subsequent device instability or configuration drift
Monitoring Recommendations
- Forward router syslog and access logs to a centralized logging or SIEM platform for retention and alerting
- Monitor for new or unauthorized administrative sessions against the router web UI
- Track devices on the network for unexpected DNS resolvers or routing changes that may indicate post-exploitation tampering
How to Mitigate CVE-2026-7219
Immediate Actions Required
- Disable remote management of the Totolink N300RT from the WAN interface
- Restrict access to the LAN-side management interface to trusted administrative hosts only
- Rotate router administrator credentials and enforce strong, unique passwords
- Review router configuration for unauthorized changes to QoS, DNS, or firewall rules
Patch Information
No vendor advisory or firmware patch has been published in the available references at the time of CVE assignment. Consult the TOTOLINK Official Website for firmware updates and apply any security release for the N300RT as soon as it becomes available.
Workarounds
- Place vulnerable routers behind a perimeter firewall and block inbound traffic to the router management ports from untrusted networks
- Segment IoT and network infrastructure devices from user and server VLANs to limit lateral movement
- Consider replacing end-of-life or unpatched consumer routers with vendor-supported models that receive timely security updates
- Monitor the VulDB CTI Analysis for updates on exploitation activity and vendor response
# Configuration example: block external access to the router management interface
# Apply on an upstream firewall protecting the Totolink N300RT
iptables -A FORWARD -p tcp -d <router_ip> --dport 80 -i <wan_interface> -j DROP
iptables -A FORWARD -p tcp -d <router_ip> --dport 443 -i <wan_interface> -j DROP
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
