Stack-Based Buffer Overflow Vulnerability in TOTOLINK X18 Router

CVE-2025-1340

What is CVE-2025-1340?

CVE-2025-1340 is a critical vulnerability identified in the TOTOLINK X18 router, specifically affecting version 9.1.0cu.2024_B20220329. This vulnerability resides in the setPasswordCfg function within the /cgi-bin/cstecgi.cgi file, leading to a stack-based buffer overflow. The potential exploitation of this vulnerability can severely compromise the security of an organization’s network, enabling remote attackers to execute malicious code and exert control over the router. This could result in unauthorized access to sensitive data and disruptions in network services, highlighting the critical need for timely interventions.

Technical Details

The vulnerability stems from a stack-based buffer overflow, which occurs when the vulnerability is exploited through the manipulation of strings. Attackers can trigger this overflow remotely, thereby circumventing normal authentication methods. The absence of effective input validation in the setPasswordCfg function allows for the potential overflow to exploit the stack memory, leading to unpredictable behavior or enabling the execution of arbitrary code within the context of the router. The flaw was publicly disclosed, and attempts to communicate with the vendor regarding its severity have gone unanswered.

Potential Impact of CVE-2025-1340

1. Remote Code Execution: The vulnerability allows attackers to execute arbitrary code on the TOTOLINK X18 router. If a successful exploitation occurs, it could enable attackers to hijack the router, launch further attacks on internal networks, or deploy additional malicious software.

2. Unauthorized Network Access: Gaining control of the router can provide unauthorized access to the entire network. This risk includes potential interception of sensitive data, unauthorized data exfiltration, and manipulation of network traffic, leading to significant information security compromises.

3. Service Disruption: Exploiting this vulnerability could lead to denial of service (DoS) conditions, disrupting the normal operation of network services. An attacker could potentially render the router inoperable or unstable, causing downtime and loss of productivity for organizations relying on network connectivity.

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