Overview
The cybersecurity community is currently faced with a critical vulnerability, identified as CVE-2025-4834, affecting a range of TOTOLINK routers. This vulnerability lies in an unknown function of the file /boafrm/formSetLg, specifically within the HTTP POST Request Handler component. It is a severe issue affecting the TOTOLINK A702R, A3002R, and A3002RU models (version 3.0.0-B20230809.1615). The exploitation of this vulnerability can lead to a buffer overflow, which can potentially compromise the system or lead to data leakage.
As the vulnerability can be exploited remotely and the exploit has been disclosed publicly, it poses a major threat to all users of the affected devices. The seriousness of this vulnerability underscores the importance of understanding its nature and mitigating its potential harm.
Vulnerability Summary
CVE ID: CVE-2025-4834
Severity: Critical (CVSS: 8.8)
Attack Vector: Network (via HTTP POST Request)
Privileges Required: None
User Interaction: None
Impact: Potential system compromise and data leakage
Affected Products
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Product | Affected Versions
TOTOLINK A702R | 3.0.0-B20230809.1615
TOTOLINK A3002R | 3.0.0-B20230809.1615
TOTOLINK A3002RU | 3.0.0-B20230809.1615
How the Exploit Works
The vulnerability resides in the manipulation of the ‘submit-url’ argument in the HTTP POST Request Handler component of the /boafrm/formSetLg file. By sending a specially crafted HTTP POST request with the manipulated ‘submit-url’ argument, an attacker can cause a buffer overflow. This overflow can overwrite critical data in memory and potentially allow the attacker to execute arbitrary code or cause the system to crash.
Conceptual Example Code
Below is a conceptual example of how this vulnerability might be exploited. The attacker sends a malicious HTTP POST request to the target device:
POST /boafrm/formSetLg HTTP/1.1
Host: target-router-ip
Content-Type: application/x-www-form-urlencoded
submit-url=<malicious_payload>Please note that `
Mitigation
At the moment, the ideal solution is to apply the patch provided by the vendor. For those who cannot implement the patch immediately, using a Web Application Firewall (WAF) or Intrusion Detection System (IDS) can serve as a temporary mitigation measure. These systems can be configured to block or alert about HTTP POST requests that appear to be exploiting this vulnerability. Updating to a version of the software that is not vulnerable is also recommended, if possible.