Overview
The CVE-2025-8817 vulnerability, identified in a range of Linksys devices, presents a serious threat to data security and system integrity. This vulnerability affects Linksys RE6250, RE6300, RE6350, RE6500, RE7000, and RE9000 devices up to version 20250801. The vulnerability, which lies in the functionality of the setLan file, can be exploited remotely, potentially leading to system compromise or data leakage. The severity of this vulnerability underscores the need for immediate action from both users and the vendor.
Vulnerability Summary
CVE ID: CVE-2025-8817
Severity: Critical (CVSS: 8.8)
Attack Vector: Remote
Privileges Required: None
User Interaction: None
Impact: Potential system compromise or data leakage
Affected Products
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Product | Affected Versions
Linksys RE6250 | Up to 20250801
Linksys RE6300 | Up to 20250801
Linksys RE6350 | Up to 20250801
Linksys RE6500 | Up to 20250801
Linksys RE7000 | Up to 20250801
Linksys RE9000 | Up to 20250801
How the Exploit Works
The vulnerability stems from a stack-based buffer overflow in the setLan function of the /goform/setLan file in the affected Linksys devices. This is triggered by the improper handling of the lan2enabled argument, which can be manipulated to overflow the buffer. This overflow can lead to arbitrary code execution, allowing an attacker to compromise the system or leak data.
Conceptual Example Code
Here’s a conceptual example of how an HTTP request exploiting this vulnerability might look:
POST /goform/setLan HTTP/1.1
Host: target_linksys_device
Content-Type: application/x-www-form-urlencoded
lan2enabled=1&lan2ipAddr=192.168.1.1&lan2SubnetMask=255.255.255.0&lan2DhcpStart=192.168.1.100&lan2DhcpEnd=192.168.1.150&lan2DhcpEnabled=1&lan2Dns1=192.168.1.1&lan2Lease=86400&lan2Domain=&lan2Gateway=192.168.1.1&lan2Dns2=192.168.1.1&lan2Dns3=192.168.1.1&lan2enabled=A*50000In the above code, the lan2enabled parameter is filled with “A*50000” which is significantly larger than what the system is designed to handle, leading to a buffer overflow.
It’s important to note that the above is a simplified example and actual exploitation may require more complex manipulation.
Mitigation
As a short-term mitigation, users are advised to use a Web Application Firewall (WAF) or Intrusion Detection System (IDS). However, the ultimate solution is the application of a vendor patch. Despite contacting the vendor about this critical disclosure, they have yet to respond. Users should stay abreast of any updates from the vendor and apply patches as soon as they become available.