CVE-2025-6621 is a security vulnerability identified in the TOTOLINK CA300-PoE router, specifically in firmware version 6.2c.884. The flaw exists within the QuickSetting function of the ap.so component, where improper handling of the 'hour' and 'minute' arguments allows for OS command injection. This vulnerability enables an attacker to remotely execute arbitrary operating system commands on the affected device without requiring user interaction or prior authentication, as indicated by the CVSS vector (AV:N/AC:L/AT:N/UI:N/PR:L). The vulnerability arises due to insufficient input validation or sanitization of parameters passed to system-level commands, allowing crafted inputs to be interpreted as executable commands. Although the CVSS 4.0 base score is 5.3 (medium severity), the exploitability is relatively straightforward given the network attack vector and lack of user interaction. The scope is limited to devices running the specified firmware version, and there is no indication of privilege escalation beyond the existing privilege level required (PR:L). No public exploit code has been confirmed in the wild yet, but the disclosure of the vulnerability and technical details increases the risk of exploitation. The vulnerability impacts the confidentiality, integrity, and availability of the device, as arbitrary command execution can lead to data leakage, device manipulation, or denial of service. The absence of patches or vendor mitigation guidance at the time of publication further elevates the risk for organizations using this device in their network infrastructure.

For European organizations, the exploitation of CVE-2025-6621 could lead to significant operational disruptions and security breaches. The TOTOLINK CA300-PoE is a Power over Ethernet (PoE) router commonly used in small to medium-sized enterprise networks and branch offices for network connectivity and management. Successful exploitation could allow attackers to gain control over network routing, intercept or manipulate traffic, and potentially pivot to other internal systems. This compromises confidentiality through data interception, integrity through unauthorized configuration changes, and availability by causing device outages or network disruptions. Given the remote attack vector and no need for user interaction, attackers could automate exploitation attempts, increasing the likelihood of widespread impact. The vulnerability is particularly concerning for organizations relying on TOTOLINK devices for critical infrastructure or sensitive communications. Additionally, the lack of a patch at the time of disclosure means organizations must rely on interim mitigations, increasing exposure duration. The medium CVSS score may underestimate the real-world impact in environments where these devices are critical network components.

1. Immediate network segmentation: Isolate TOTOLINK CA300-PoE devices from critical network segments to limit potential lateral movement if compromised. 2. Access control: Restrict management interfaces to trusted IP addresses and implement strict firewall rules to limit exposure of vulnerable services. 3. Monitor network traffic: Deploy intrusion detection/prevention systems (IDS/IPS) with signatures tuned to detect unusual command injection patterns or suspicious activity targeting the QuickSetting function. 4. Firmware upgrade: Engage with TOTOLINK support to obtain patched firmware or updates addressing this vulnerability as soon as they become available. 5. Disable or restrict QuickSetting functionality if possible, or remove remote management capabilities temporarily until a patch is applied. 6. Conduct regular vulnerability scans and penetration tests focusing on network devices to identify similar injection flaws. 7. Maintain detailed logs and enable alerting on configuration changes or unexpected command executions on affected devices. 8. Educate network administrators about the vulnerability and ensure strict operational procedures to minimize risk during the interim period.