CVE-2025-45790 in A3100R
Summary
by MITRE • 05/08/2025
TOTOLINK A3100R V5.9c.1527 is vulnerable to Buffer Overflow via the priority parameter in the setMacQos interface of /lib/cste_modules/firewall.so.
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Analysis
by VulDB Data Team • 05/13/2025
The vulnerability identified as CVE-2025-45790 affects the TOTOLINK A3100R router model running firmware version V5.9c.1527 and represents a critical buffer overflow condition within the device's firewall module. This issue manifests through the setMacQos interface located in the /lib/cste_modules/firewall.so library, which processes incoming requests containing a priority parameter. The flaw enables an attacker to potentially execute arbitrary code or cause system instability by sending maliciously crafted input data that exceeds the allocated buffer space. Such vulnerabilities are particularly dangerous in network infrastructure devices as they can provide attackers with unauthorized access to the underlying system and potentially enable further exploitation within the network perimeter.
The technical nature of this buffer overflow stems from improper input validation within the firewall.so module's handling of the priority parameter in the setMacQos interface. When the system receives a request with an oversized priority value, the application fails to properly bounds-check the input data before copying it into a fixed-size buffer. This classic programming error allows attackers to overwrite adjacent memory locations, potentially corrupting critical system data or executing malicious code. The vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions, and may also relate to CWE-787, representing out-of-bounds write conditions that can occur when input validation is insufficient. From an operational perspective, this vulnerability can be exploited through network-based attacks targeting the router's web interface or API endpoints that utilize the affected firewall module.
The operational impact of this vulnerability extends beyond simple system crashes or denial of service conditions. Attackers could potentially leverage this buffer overflow to gain unauthorized administrative access to the router's management interface, allowing them to modify network configurations, establish persistent backdoors, or redirect network traffic. The attack surface is particularly concerning given that the vulnerability exists within a core firewall module that controls network traffic prioritization and Quality of Service settings. According to ATT&CK framework categorization, this vulnerability would map to T1068, which covers 'Exploitation for Privilege Escalation', and potentially T1566, covering 'Phishing for Information', if attackers use social engineering to gain initial access. The affected device's web-based management interface creates multiple attack vectors, including potential cross-site scripting or command injection scenarios that could be amplified by this buffer overflow condition.
Mitigation strategies for CVE-2025-45790 should prioritize immediate firmware updates from TOTOLINK, if available, as this represents the most effective defense against the known vulnerability. Network administrators should implement network segmentation and access controls to limit exposure of affected devices to untrusted networks or users. Additionally, monitoring network traffic for unusual patterns or malformed requests targeting the setMacQos interface can help detect exploitation attempts. Security teams should also consider implementing intrusion detection systems that can identify potential buffer overflow exploitation patterns, particularly in the firewall module's handling of QoS parameters. Regular security assessments of network infrastructure devices are essential to identify similar vulnerabilities in other firmware components. The vulnerability demonstrates the importance of input validation and proper memory management in embedded systems, and organizations should review their security practices to ensure that all network devices undergo thorough security testing before deployment.