Overview
A critical security vulnerability, dubbed CVE-2025-57085, has been identified in the Tenda W30E V16.01.0.19 (5037) router. This flaw, if exploited, could allow cyber attackers to cause a Denial of Service (DoS) attack, effectively disrupting the operation of the targeted network and potentially compromising system data. Given the widespread use of Tenda routers in homes and businesses worldwide, this vulnerability poses a significant threat and demands immediate attention and mitigation.
Vulnerability Summary
CVE ID: CVE-2025-57085
Severity: Critical (CVSS 9.8)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: Denial of Service, potential system compromise, and data leakage
Affected Products
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Product | Affected Versions
Tenda W30E | V16.01.0.19 (5037)
How the Exploit Works
The vulnerability stems from a stack overflow in the v17 parameter in the UploadCfg function of the Tenda W30E routers. A stack overflow is a common software vulnerability where the stack, a region of a computer’s memory space, is filled beyond its capacity. When this occurs, the excess data can overwrite adjacent memory locations, causing erratic program behavior, including memory access errors, incorrect results, program termination, or a breach of system security.
In the case of CVE-2025-57085, an attacker can send a specially crafted request to Tenda routers, causing a stack overflow in the v17 parameter of the UploadCfg function. This overflow can then lead to a DoS condition, disrupting the router’s functionality, and potentially allowing further exploitation leading to system compromise and data leakage.
Conceptual Example Code
Below is a conceptual example of how an attacker might exploit this vulnerability. Note that the actual payload would likely be more complex and designed to cause a stack overflow.
POST /UploadCfg HTTP/1.1
Host: target.example.com
Content-Type: application/json
{
"v17": "A"*10000 // a sequence of characters 'A' repeated 10,000 times to overflow the stack
}This HTTP request attempts to upload a configuration with the “v17” parameter value exceeding the stack’s capacity, causing the overflow.
Mitigation and Remediation
Tenda has provided a patch to address this critical vulnerability. All users of the affected router model are strongly urged to apply this patch immediately. If immediate patching is not possible, users are advised to use a Web Application Firewall (WAF) or an Intrusion Detection System (IDS) as temporary mitigation measures. These systems can help detect and block suspicious requests, potentially preventing the exploitation of this vulnerability.
