CVE-2026-7100: Tenda F456 Router Vulnerability Allows Remote Buffer Overflow
The National Vulnerability Database (NVD) has disclosed CVE-2026-7100, a high-severity buffer overflow vulnerability impacting the Tenda F456 1.0.0.5 router. The flaw resides in the fromNatlimitof function within the /goform/Natlimit component of the httpd service.
This vulnerability, rated 8.8 CVSS (High), can be exploited remotely with low privileges (PR:L), meaning an attacker only needs basic user access to the device. Successful exploitation leads to a buffer overflow, potentially allowing for arbitrary code execution or a denial-of-service condition. The NVD notes that exploit code for this vulnerability has been published, increasing the immediate risk for unpatched devices.
For defenders, the implications are clear: exposed Tenda F456 routers are prime targets. Given the remote exploitability and public availability of exploit code, any organization or individual using this specific router model needs to take immediate action. This isn’t theoretical; it’s an active threat that will be quickly weaponized.
What This Means For You
- If your organization or any connected remote offices utilize the Tenda F456 1.0.0.5 router, you must immediately assess its exposure. This vulnerability presents a critical attack surface for network compromise. Isolate or replace these devices until a patch is available. Assume compromise if they are internet-facing and unpatched.
Related ATT&CK Techniques
🛡️ Detection Rules
2 rules · 6 SIEM formats2 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.
CVE-2026-7100: Tenda F456 Router Natlimitof Buffer Overflow Attempt
title: CVE-2026-7100: Tenda F456 Router Natlimitof Buffer Overflow Attempt
id: scw-2026-04-27-ai-1
status: experimental
level: critical
description: |
Detects attempts to exploit CVE-2026-7100 by targeting the vulnerable /goform/Natlimit endpoint on Tenda F456 routers. This rule specifically looks for POST requests to this URI containing the 'limit=' parameter, which is part of the buffer overflow exploit chain.
author: SCW Feed Engine (AI-generated)
date: 2026-04-27
references:
- https://shimiscyberworld.com/posts/nvd-CVE-2026-7100/
tags:
- attack.initial_access
- attack.t1190
logsource:
category: webserver
detection:
selection:
cs-uri|contains:
- '/goform/Natlimit'
cs-method|exact:
- 'POST'
cs-uri-query|contains:
- 'limit='
condition: selection
falsepositives:
- Legitimate administrative activity
Source: Shimi's Cyber World · License & reuse
Indicators of Compromise
| ID | Type | Indicator |
|---|---|---|
| CVE-2026-7100 | Buffer Overflow | Tenda F456 version 1.0.0.5 |
| CVE-2026-7100 | Buffer Overflow | Vulnerable component: httpd |
| CVE-2026-7100 | Buffer Overflow | Vulnerable function: fromNatlimitof in /goform/Natlimit |
Written by SCW Vulnerability Desk
Source & Attribution
| Source Platform | NVD |
| Channel | National Vulnerability Database |
| Published | April 27, 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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