Overview
A critical vulnerability, CVE-2025-9526, has been identified in the Linksys E1700 router, version 1.0.0.4.003. This vulnerability allows for a stack-based buffer overflow attack, which could potentially lead to a complete system compromise or data leakage. This issue affects a broad range of users, specifically anyone using the affected version of the Linksys E1700 router. Given the role of routers in handling network traffic, the exploitation of this vulnerability could provide attackers with significant control over a network, which makes this a matter of high concern.
Vulnerability Summary
CVE ID: CVE-2025-9526
Severity: High (8.8 CVSS Score)
Attack Vector: Remote
Privileges Required: None
User Interaction: None
Impact: Potential system compromise and data leakage
Affected Products
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Product | Affected Versions
Linksys E1700 | 1.0.0.4.003
How the Exploit Works
The vulnerability lies within the ‘setSysAdm’ function of the ‘/goform/setSysAdm’ file. The issue is caused by improper validation of user-supplied data, which can result in a stack-based buffer overflow condition. An attacker may exploit this vulnerability by manipulating the ‘rm_port’ argument to trigger the overflow. This can lead to the execution of arbitrary code in the context of the affected application, making it possible for an attacker to gain control over the system.
Conceptual Example Code
Below is a conceptual example of how the vulnerability might be exploited. In this example, we’re manipulating the ‘rm_port’ argument in an HTTP POST request to the vulnerable endpoint:
POST /goform/setSysAdm HTTP/1.1
Host: vulnerable-linksys-router
Content-Type: application/x-www-form-urlencoded
rm_port=65537; //This value is larger than expected, triggering the buffer overflowThis code sends a request to the vulnerable endpoint with a larger ‘rm_port’ value than expected, which can trigger the buffer overflow. Note that this is a conceptual example; the precise payload would depend on the specific system setup and desired outcome of the attack.
Mitigation
Users are strongly advised to apply the vendor-supplied patch to fix this vulnerability as soon as possible. If the patch is not available, temporary mitigation can be achieved by using a Web Application Firewall (WAF) or Intrusion Detection System (IDS) to detect and block attempts to exploit this vulnerability. However, these are not long-term solutions and the patch should be applied as soon as it becomes available.
