Totolink N300RH Router Hit by High-Severity Buffer Overflow Vulnerability (CVE-2026-7749)
The National Vulnerability Database has disclosed CVE-2026-7749, a critical buffer overflow vulnerability affecting Totolink N300RH routers running firmware version 3.2.4-B20220812. This flaw resides within the POST Request Handler component, specifically in the /cgi-bin/cstecgi.cgi file. Attackers can exploit this by manipulating the priDns argument, leading to a buffer overflow that can be initiated remotely. The National Vulnerability Database rates this vulnerability at CVSS 8.8 (HIGH), indicating a significant risk.
This vulnerability (CWE-119, CWE-120) presents a serious remote code execution risk for organizations relying on these devices. Given the public disclosure and high CVSS score, attackers are likely to weaponize this exploit. Defenders must prioritize patching or isolating affected devices immediately. The lack of specified affected products beyond the model and firmware version means a broad sweep of network infrastructure is advisable to identify potential exposures.
What This Means For You
- If your organization utilizes Totolink N300RH routers, immediately verify firmware versions and apply patches if available. Given the remote exploitability and high severity, prioritize isolating any identified vulnerable devices from the internet and internal critical networks until they can be remediated. Audit network logs for any unusual activity originating from or targeting these devices.
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-2026-7749
title: Web Application Exploitation Attempt — CVE-2026-7749
id: scw-2026-05-04-1
status: experimental
level: high
description: |
Detects common exploitation patterns targeting web applications. Review CVE-2026-7749 advisories for specific indicators.
author: SCW Feed Engine (auto-generated)
date: 2026-05-04
references:
- https://shimiscyberworld.com/posts/nvd-CVE-2026-7749/
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-2026-7749
Source: Shimi's Cyber World · License & reuse
Indicators of Compromise
| ID | Type | Indicator |
|---|---|---|
| CVE-2026-7749 | Buffer Overflow | Totolink N300RH version 3.2.4-B20220812 |
| CVE-2026-7749 | Buffer Overflow | Vulnerable function: setWanConfig in /cgi-bin/cstecgi.cgi |
| CVE-2026-7749 | Buffer Overflow | Vulnerable argument: priDns in POST Request Handler |
Written by SCW Vulnerability Desk
Source & Attribution
| Source Platform | NVD |
| Channel | National Vulnerability Database |
| Published | May 04, 2026 at 13:16 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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