Overview
The cybersecurity world has witnessed the emergence of a new high-severity vulnerability in the TOTOLINK A702R 4.0.0-B20211108.1423. This vulnerability, labeled as CVE-2025-9779, involves a buffer overflow that occurs within the function sub_4162DC of the file /boafrm/formFilter. It is a serious issue as the vulnerability can be exploited remotely, making various systems prone to potential compromise or data leakage. The exploit is public, which increases the risk of it being used by malicious entities.
Vulnerability Summary
CVE ID: CVE-2025-9779
Severity: High (CVSS 8.8)
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
TOTOLINK A702R | 4.0.0-B20211108.1423
How the Exploit Works
The vulnerability arises from a buffer overflow condition in the function sub_4162DC of the file /boafrm/formFilter. This occurs when an oversized, specially crafted ‘ip6addr’ argument is passed to this function. The function does not properly validate the length of this argument which results in a buffer overflow. An attacker can exploit this vulnerability by sending a specially crafted request to the targeted system, leading to arbitrary code execution or even system crash.
Conceptual Example Code
Here is a conceptual example of how the vulnerability might be exploited. This is a hypothetical HTTP request, where an attacker sends a malicious payload in the ‘ip6addr’ field.
POST /boafrm/formFilter HTTP/1.1
Host: target.example.com
Content-Type: application/json
{ "ip6addr": "2001:0db8:85a3:0000:0000:8a2e:0370:7334aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa..." }In this example, the value of ‘ip6addr’ is deliberately oversized, causing a buffer overflow in the function sub_4162DC.
Mitigation Guidance
Users are advised to apply the vendor patch as soon as it becomes available. In the meantime, the use of a Web Application Firewall (WAF) or an Intrusion Detection System (IDS) can serve as a temporary mitigation, helping to detect and potentially block attempts to exploit this vulnerability. Additionally, users should monitor any suspicious network activity and ensure that their systems are updated with the latest security patches and updates.
