CVE-2025-44836 is a command injection vulnerability identified in the TOTOLINK CPE CP900 router firmware version V6.3c.1144_B20190715. The flaw exists in the setApRebootScheCfg function, which handles scheduling parameters for rebooting the device. Specifically, the vulnerability arises from improper input validation of the 'hour' and 'minute' parameters, allowing an attacker to inject arbitrary commands through crafted requests. This type of injection corresponds to CWE-77 (Improper Neutralization of Special Elements used in a Command). Exploiting this vulnerability enables remote attackers to execute arbitrary system commands on the affected device without requiring user interaction. The CVSS v3.1 base score is 6.3 (medium severity), with the vector AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L, indicating network attack vector, low attack complexity, requiring low privileges, no user interaction, unchanged scope, and low impact on confidentiality, integrity, and availability. Although no known exploits are currently reported in the wild, the vulnerability's nature allows for potentially impactful remote command execution, which could lead to unauthorized control over the device, manipulation of network traffic, or pivoting to internal networks. The lack of available patches or vendor advisories at this time increases the risk for affected users. TOTOLINK CPE CP900 devices are commonly used as consumer and small office routers, making this vulnerability relevant for environments relying on these devices for network connectivity and security functions.

For European organizations, especially small and medium enterprises (SMEs) and residential users relying on TOTOLINK CPE CP900 routers, this vulnerability poses a significant risk. Successful exploitation could lead to unauthorized command execution on network gateways, potentially compromising network integrity and availability. Attackers might leverage this to intercept or redirect traffic, deploy malware, or establish persistent footholds within internal networks. Given the low privilege requirement but network-based attack vector, attackers with some level of access (e.g., via compromised internal hosts or exposed management interfaces) could exploit this vulnerability remotely. The impact on confidentiality, integrity, and availability is moderate but could escalate if attackers use the compromised device as a launchpad for further attacks. Additionally, the absence of patches means that affected organizations remain exposed until mitigations or updates are applied. This vulnerability could disrupt business operations, lead to data breaches, or degrade network performance, particularly in sectors where network reliability and security are critical.

1. Immediate network segmentation: Isolate TOTOLINK CPE CP900 devices from critical network segments to limit potential lateral movement if compromised. 2. Restrict management interface access: Limit access to the router's management interfaces (e.g., web UI, SSH) to trusted IP addresses only, preferably via VPN or secure channels. 3. Monitor network traffic and logs: Implement enhanced monitoring for unusual outbound connections or command execution patterns originating from the router. 4. Disable or restrict the setApRebootScheCfg functionality if possible, or avoid using scheduled reboot features until a patch is available. 5. Regularly audit device firmware versions and configurations to identify affected devices. 6. Engage with TOTOLINK support or vendors for firmware updates or patches addressing this vulnerability. 7. Employ network intrusion detection/prevention systems (IDS/IPS) with signatures targeting command injection attempts on router management interfaces. 8. Educate users and administrators about the risks of exposing router management interfaces to untrusted networks and the importance of strong authentication and access controls.