CVE-2025-39348 is a critical security vulnerability identified in the ThemeGoods Grand Restaurant WordPress plugin, affecting versions up to 7.0. The vulnerability is classified under CWE-502, which pertains to Deserialization of Untrusted Data. This type of vulnerability occurs when untrusted input is deserialized by an application, potentially allowing an attacker to manipulate serialized objects to perform malicious actions such as object injection. In this case, the vulnerability allows an attacker to inject arbitrary objects during the deserialization process, which can lead to remote code execution, privilege escalation, or other severe impacts on the affected system. The CVSS v3.1 base score of 9.8 reflects the critical nature of this vulnerability, with an attack vector that is network-based (AV:N), requiring no privileges (PR:N) and no user interaction (UI:N). The vulnerability affects confidentiality, integrity, and availability (C:H/I:H/A:H), indicating that exploitation could lead to full system compromise. No patches or fixes are currently linked, and no known exploits have been reported in the wild as of the publication date. However, given the severity and ease of exploitation, this vulnerability poses a significant risk to websites using the Grand Restaurant WordPress plugin, especially those exposed to the internet without additional protective controls.

For European organizations, the impact of CVE-2025-39348 can be substantial. Many small to medium-sized enterprises (SMEs) and hospitality-related businesses in Europe rely on WordPress and its plugins like Grand Restaurant for their online presence and booking systems. Exploitation of this vulnerability could lead to unauthorized access, data breaches involving customer and payment information, defacement of websites, and disruption of online services. This could result in reputational damage, regulatory penalties under GDPR for data breaches, and financial losses. Additionally, compromised websites could be used as pivot points for further attacks within corporate networks or for distributing malware. The critical severity and network-level exploitability mean that attackers can remotely compromise vulnerable sites without any user interaction, increasing the risk of widespread exploitation if the vulnerability is not addressed promptly.

Given the absence of an official patch at the time of this report, European organizations should take immediate and specific mitigation steps beyond generic advice: 1) Disable or remove the Grand Restaurant WordPress plugin if it is not essential to reduce the attack surface. 2) Implement Web Application Firewalls (WAFs) with custom rules to detect and block suspicious serialized data patterns or unusual POST requests targeting the plugin endpoints. 3) Restrict access to the WordPress admin and plugin-related endpoints using IP whitelisting or VPN access to limit exposure. 4) Monitor web server and application logs for anomalous activity indicative of deserialization attacks, such as unexpected serialized payloads or error messages related to object injection. 5) Employ runtime application self-protection (RASP) tools that can detect and prevent deserialization attacks in real-time. 6) Prepare for rapid patch deployment by subscribing to vendor and security mailing lists and testing updates in staging environments. 7) Conduct regular backups and ensure recovery plans are in place to mitigate potential damage from exploitation.