CVE-2025-64053 is a buffer overflow vulnerability identified in Fanvil X210 IP phones running firmware version 2.12.20. The flaw exists in the device's web management interface, specifically at the /cgi-bin/webconfig?page=upload&action=submit endpoint, which handles POST requests related to configuration uploads. Due to insufficient bounds checking on input data, an attacker can craft a malicious POST request that overflows a buffer, leading to memory corruption. This can result in a denial of service (crashing the device) or potentially arbitrary command execution, allowing the attacker to run code on the device remotely. The vulnerability requires no authentication or user interaction, making it remotely exploitable over the network. The CVSS v3.1 base score is 7.5, reflecting network attack vector, low attack complexity, no privileges required, no user interaction, and impact limited to availability. The vulnerability is classified under CWE-120, a common weakness related to classic buffer overflows. No patches or official mitigations have been published at the time of disclosure, and no active exploits have been reported. This vulnerability poses a significant risk to organizations relying on Fanvil X210 devices for VoIP communications, as exploitation could disrupt telephony services or compromise device integrity.

For European organizations, this vulnerability could disrupt critical VoIP communications by causing device crashes or enabling attackers to execute arbitrary commands on Fanvil X210 phones. This could lead to denial of service in enterprise telephony systems, impacting business operations and customer communications. In sectors such as finance, healthcare, and government where reliable communication is essential, the impact could be severe. Additionally, if exploited for command execution, attackers might pivot within internal networks or intercept sensitive communications. The lack of authentication and user interaction requirements increases the risk of widespread exploitation, especially in environments where these devices are exposed to untrusted networks or insufficiently segmented. The absence of patches means organizations must rely on compensating controls, increasing operational complexity and risk exposure.

1. Immediately restrict network access to the management interface of Fanvil X210 devices, especially the /cgi-bin/webconfig endpoint, using firewalls or access control lists to allow only trusted management hosts. 2. Implement network segmentation to isolate VoIP devices from general user and internet-facing networks, reducing exposure to remote attacks. 3. Monitor network traffic for unusual POST requests targeting the vulnerable endpoint, employing intrusion detection systems with custom signatures if possible. 4. Disable or limit web management interfaces if not required, or move management access to secure, out-of-band networks. 5. Engage with Fanvil or authorized vendors to obtain firmware updates or patches as soon as they become available. 6. Conduct regular security assessments of VoIP infrastructure to identify and remediate similar vulnerabilities proactively. 7. Educate IT and security teams about this vulnerability to ensure rapid response and incident handling if exploitation attempts are detected.