Buffer Overflow in Totolink A3002MU Router Firmware

Executive Summary

CVE-2026-90607 is a buffer overflow vulnerability in the Totolink A3002MU router's web server component called Boa. The issue occurs in the formNewSchedule function when processing the submit-url parameter. The program copies this parameter into a fixed-size buffer without checking its length, allowing an attacker to send a specially crafted HTTP request with an overly long submit-url value. This causes memory corruption and crashes the Boa process, leading to a denial-of-service condition where the router's management interface becomes unresponsive.

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Detection Guidance

To detect this vulnerability, monitor network traffic for HTTP POST requests to /boafrm/formNewSchedule with unusually long submit-url parameters. Use tools like tcpdump or Wireshark to capture and inspect traffic. Check router logs for crashes or unresponsive management interfaces.

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Impact Analysis

This vulnerability allows a remote attacker to crash the router's web interface by sending a malicious HTTP request. The impact includes loss of router management access, potential loss of internet connectivity, and disruption of network services. An attacker could exploit this to make the device unusable until manually rebooted. Since the attack is remote and requires no authentication beyond network access, it poses a significant risk for home and small office networks using this router model.

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Mitigation Strategies

Immediately update the router firmware to a patched version if available. Disable remote management access to the router if not required. Block external access to the /boafrm/formNewSchedule endpoint using firewall rules until a patch is applied.

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