CVE-2025-7912 in TOTOLINK
Summary
by MITRE • 07/21/2025
A vulnerability, which was classified as critical, has been found in TOTOLINK T6 4.1.5cu.748_B20211015. This issue affects the function recvSlaveUpgstatus of the component MQTT Service. The manipulation of the argument s 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 • 07/24/2025
The vulnerability identified as CVE-2025-7912 represents a critical buffer overflow flaw within the TOTOLINK T6 router firmware version 4.1.5cu.748_B20211015. This security weakness resides in the MQTT Service component, specifically within the recvSlaveUpgstatus function where improper input validation occurs. The buffer overflow vulnerability manifests when processing the argument s, which suggests that the device fails to adequately validate or sanitize incoming data from MQTT communications. This critical weakness arises from inadequate bounds checking and memory management practices that allow attackers to manipulate the s parameter to exceed allocated buffer boundaries, potentially leading to arbitrary code execution or system compromise.
The technical exploitation of this vulnerability occurs through remote attack vectors, making it particularly dangerous as it does not require physical access to the device or local network presence. The disclosed exploit demonstrates that attackers can leverage the MQTT service interface to send maliciously crafted payloads that trigger the buffer overflow condition. This remote exploitation capability aligns with attack patterns documented in the MITRE ATT&CK framework under the technique of remote code execution through protocol manipulation. The vulnerability's classification as critical stems from its potential to allow full system compromise, including unauthorized access to network resources, data exfiltration, and the ability to establish persistent backdoors within the affected network infrastructure.
The operational impact of CVE-2025-7912 extends beyond individual device compromise to encompass broader network security implications. As an MQTT service vulnerability, it affects not only the specific TOTOLINK T6 device but potentially any network infrastructure relying on MQTT communications for device management or monitoring. The buffer overflow condition could result in system crashes, denial of service conditions, or complete system takeover, depending on the execution context and payload delivery method. Organizations utilizing these routers for network management or IoT deployments face significant risk of unauthorized access to their infrastructure, particularly in environments where MQTT services are used for firmware updates or device status reporting.
Mitigation strategies for this vulnerability should prioritize immediate firmware updates from TOTOLINK, as the manufacturer is likely to release patches addressing the buffer overflow condition in the recvSlaveUpgstatus function. Network segmentation and access control measures should be implemented to limit exposure of MQTT services to trusted networks only, following the principle of least privilege as recommended by cybersecurity frameworks such as NIST SP 800-53. Additionally, network monitoring should be enhanced to detect anomalous MQTT traffic patterns that might indicate exploitation attempts. The vulnerability also highlights the importance of input validation and secure coding practices, particularly in embedded systems where resource constraints often lead to insufficient security controls. Organizations should consider implementing intrusion detection systems that can identify buffer overflow patterns and ensure proper network hygiene through regular vulnerability assessments and penetration testing to identify similar weaknesses in other network infrastructure components.