CVE-2025-5902 in T10
Summary
by MITRE • 06/10/2025
A vulnerability was found in TOTOLINK T10 4.1.8cu.5207 and classified as critical. This issue affects the function setUpgradeFW of the file /cgi-bin/cstecgi.cgi of the component POST Request Handler. The manipulation of the argument slaveIpList leads to buffer overflow. The attack may be initiated remotely. The exploit has been disclosed to the public and may be used.
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Analysis
by VulDB Data Team • 06/16/2025
The vulnerability identified as CVE-2025-5902 represents a critical buffer overflow condition within the TOTOLINK T10 router firmware version 4.1.8cu.5207. This flaw exists in the setUpgradeFW function of the /cgi-bin/cstecgi.cgi component which processes POST requests from remote clients. The specific weakness occurs when handling the slaveIpList argument, which allows an attacker to provide input that exceeds the allocated buffer space. This type of vulnerability falls under CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking permits data to overwrite adjacent memory locations. The affected device operates as a network gateway and router, making it a prime target for attackers seeking to compromise network infrastructure.
The technical exploitation of this vulnerability occurs through a remote POST request to the affected cgi-bin endpoint, where the slaveIpList parameter is processed without adequate input validation or buffer size checking. When an attacker crafts a malicious payload containing an excessively long slaveIpList value, the system's memory management fails to properly handle the overflow condition, potentially allowing arbitrary code execution or system crash. The attack vector is particularly dangerous because it requires no local access or authentication, enabling remote exploitation from any network location. This vulnerability demonstrates poor input sanitization practices that violate security best practices outlined in the OWASP Top Ten and represents a significant risk to network security.
The operational impact of this vulnerability extends beyond simple denial of service conditions to potentially enable full system compromise. An attacker who successfully exploits this buffer overflow could gain unauthorized access to the router's administrative functions, allowing them to modify network configurations, redirect traffic, or establish persistent backdoors. The implications are severe for any organization relying on TOTOLINK T10 devices, as these routers often serve as primary network gateways and may control access to critical internal systems. The public disclosure of exploitation techniques further amplifies the risk, as malicious actors can readily leverage this vulnerability without requiring advanced technical skills. This scenario aligns with ATT&CK technique T1210, which describes exploitation of remote services for privilege escalation and persistent access.
Mitigation strategies for CVE-2025-5902 should prioritize immediate firmware updates from TOTOLINK, as the vendor has likely released patches addressing this specific buffer overflow condition. Network administrators should implement strict firewall rules to restrict access to the affected cgi-bin endpoint, particularly blocking external access to POST request handlers. Additional protective measures include deploying intrusion detection systems that monitor for suspicious POST requests containing malformed slaveIpList parameters, implementing network segmentation to isolate affected devices, and conducting comprehensive vulnerability assessments of all network equipment. Organizations should also consider disabling unnecessary services and features that might expose the vulnerable endpoint to external networks. The remediation process should follow established security protocols including change management procedures and thorough testing of firmware updates to ensure compatibility and prevent service disruption. Given the critical nature of this vulnerability, immediate action is required to protect network infrastructure from potential exploitation.