Overview
In this blog post, we delve into a critical vulnerability identified in several Linksys range extenders, specifically the RE6250, RE6300, RE6350, RE6500, RE7000, and RE9000 models. These models are widely used to extend the range of WiFi networks in homes and businesses, making this vulnerability a pressing concern. It has the potential to compromise systems or result in data leakage, impacting privacy and security on a large scale.
This vulnerability, designated as CVE-2025-9249, is particularly dangerous due to its remote exploitability and potential for system-wide damage. Despite early notification to the vendor, there has been no response or remedy, which underscores the critical importance of understanding this vulnerability and taking steps to mitigate its impact.
Vulnerability Summary
CVE ID: CVE-2025-9249
Severity: High (8.8 CVSS Score)
Attack Vector: Network
Privileges Required: None
User Interaction: None
Impact: Potential system compromise or data leakage
Affected Products
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Product | Affected Versions
Linksys RE6250 | 1.0.013.001
Linksys RE6300 | 1.0.04.001
Linksys RE6350 | 1.0.04.002
Linksys RE6500 | 1.1.05.003
Linksys RE7000 | 1.2.07.001
Linksys RE9000 | 1.2.07.001
How the Exploit Works
The vulnerability resides in the DHCPReserveAddGroup function of the /goform/DHCPReserveAddGroup file. The function mishandles the manipulation of the argument enable_group/name_group/ip_group/mac_group, leading to a stack-based buffer overflow. This can be exploited remotely by a malicious actor who sends specially crafted data to overflow the buffer, leading to erratic program behavior or even system crash.
Conceptual Example Code
A conceptual representation of how the vulnerability might be exploited is provided below:
POST /goform/DHCPReserveAddGroup HTTP/1.1
Host: target.example.com
Content-Type: application/x-www-form-urlencoded
enable_group=1&name_group=Test&ip_group=192.168.1.1&mac_group=A1:B2:C3:D4:E5:F6&extra_data=...overflown_data...In this example, the `extra_data` parameter contains the overflow data that exploits the buffer overflow vulnerability. Please note that this is a conceptual example and real-world exploits may vary based on specific conditions and the attacker’s intent.
Countermeasures and Mitigation
As of the time of writing, the vendor has not released any patch or update to address this vulnerability. As a temporary measure, users are advised to use a Web Application Firewall (WAF) or an Intrusion Detection System (IDS) to detect and prevent potential exploits. As always, it is recommended to keep all software and hardware up-to-date and to maintain proper security hygiene.