CVE-2025-48826 is a format string vulnerability classified under CWE-134, found in the formPingCmd functionality of the Planet WGR-500 router firmware version v1.3411b190912. Format string vulnerabilities occur when user-controllable input is unsafely used as a format string parameter in functions like printf, leading to memory corruption. In this case, an attacker can send a series of specially crafted HTTP requests to the router's web interface, exploiting the vulnerability to corrupt memory. This can result in arbitrary code execution, denial of service, or unauthorized disclosure/modification of sensitive data. The vulnerability requires network access and low privileges (PR:L), does not require user interaction (UI:N), and affects confidentiality, integrity, and availability (C:H/I:H/A:H). The CVSS 3.1 base score is 8.8, indicating high severity. No patches or exploits are currently reported, but the vulnerability's nature and ease of exploitation make it a critical concern for affected devices. The vulnerability's exploitation scope is limited to the specific firmware version, but given the router's deployment in various environments, the impact can be widespread.

For European organizations, exploitation of CVE-2025-48826 could lead to significant operational disruptions, including denial of service of critical network infrastructure. Confidential data passing through or stored on the affected routers could be exposed or altered, compromising privacy and data integrity. Attackers could gain control over the device, enabling lateral movement within networks or persistent access. This is particularly concerning for sectors relying on Planet WGR-500 routers for secure communications, such as small to medium enterprises, educational institutions, and some government agencies. The high severity and ease of exploitation increase the risk of targeted attacks or automated scanning campaigns. Disruptions could affect business continuity, regulatory compliance (e.g., GDPR), and trust in network security.

Since no official patches are currently available, organizations should implement immediate network-level mitigations. These include restricting access to the router's management interface to trusted IP addresses only, preferably via VPN or internal networks. Deploy web application firewalls (WAFs) or intrusion prevention systems (IPS) to detect and block suspicious HTTP requests targeting the formPingCmd functionality. Monitor network traffic for unusual patterns indicative of exploitation attempts. Disable or restrict the vulnerable functionality if possible. Plan for prompt firmware updates once a patch is released by Planet. Additionally, conduct asset inventories to identify all devices running the affected firmware version and prioritize their remediation. Employ network segmentation to limit potential lateral movement if a device is compromised.