Totolink N300RH Critical Buffer Overflow: Public Exploit Available
A critical buffer overflow vulnerability, identified as CVE-2026-7747, has been discovered in Totolink N300RH firmware version 3.2.4-B20220812. The National Vulnerability Database reports this flaw resides within the loginauth function of the /cgi-bin/cstecgi.cgi file, specifically impacting the parameter handler component.
Attackers can trigger this vulnerability remotely by manipulating the Password argument, leading to a buffer overflow. This is a severe issue, rated 9.8 (Critical) on the CVSS scale, with a vector indicating network-exploitable, low attack complexity, no privileges required, and no user interaction, resulting in complete compromise of confidentiality, integrity, and availability. The public release of an exploit dramatically increases the immediate risk.
This isn’t theoretical. A remote, unauthenticated buffer overflow with a public exploit means these devices are prime targets for botnets, initial access brokers, and state-sponsored groups looking for easy footholds. Defenders need to recognize the immediate threat posed by exposed Totolink N300RH devices.
What This Means For You
- If your organization or home network uses a Totolink N300RH router running firmware 3.2.4-B20220812, consider it compromised until proven otherwise. This is a critical remote code execution vector. Immediately isolate these devices from your main network, if possible, and implement strict network segmentation. Patching is the only real solution, but if no patch is available, replacement or removal from service should be a top priority. Do not expose these devices directly to the internet.
Related ATT&CK Techniques
🛡️ Detection Rules
5 rules · 6 SIEM formats5 detection rules auto-generated for this incident, mapped to MITRE ATT&CK. Sigma YAML is free — export to any SIEM format via the Intel Bot.
Web Application Exploitation Attempt — CVE-2026-7747
title: Web Application Exploitation Attempt — CVE-2026-7747
id: scw-2026-05-04-1
status: experimental
level: high
description: |
Detects common exploitation patterns targeting web applications. Review CVE-2026-7747 advisories for specific indicators.
author: SCW Feed Engine (auto-generated)
date: 2026-05-04
references:
- https://shimiscyberworld.com/posts/nvd-CVE-2026-7747/
tags:
- attack.initial_access
- attack.t1190
logsource:
category: webserver
detection:
selection:
cs-uri-query|contains:
- '..'
- 'SELECT'
- 'UNION'
- '<script'
- 'cmd='
- '/etc/passwd'
condition: selection
falsepositives:
- Legitimate activity from CVE-2026-7747
Source: Shimi's Cyber World · License & reuse
Indicators of Compromise
| ID | Type | Indicator |
|---|---|---|
| CVE-2026-7747 | Buffer Overflow | Totolink N300RH version 3.2.4-B20220812 |
| CVE-2026-7747 | Buffer Overflow | Vulnerable function: loginauth in /cgi-bin/cstecgi.cgi |
| CVE-2026-7747 | Buffer Overflow | Vulnerable component: Parameter Handler, argument: Password |
Written by SCW Vulnerability Desk
Source & Attribution
| Source Platform | NVD |
| Channel | National Vulnerability Database |
| Published | May 04, 2026 at 12:16 UTC |
This content was AI-rewritten and enriched by Shimi's Cyber World based on the original source. All intellectual property rights remain with the original author.
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