CVE-2025-58619 is a deserialization of untrusted data vulnerability found in the sbouey Falang multilanguage plugin, versions up to 1.3.65. Deserialization vulnerabilities occur when untrusted input is processed by an application’s deserialization mechanism, allowing attackers to inject malicious objects. In this case, the vulnerability enables object injection, which can lead to remote code execution or other malicious actions. The vulnerability is remotely exploitable over the network (AV:N), requires low attack complexity (AC:L), does not require privileges (PR:N), but does require user interaction (UI:R). The scope is unchanged (S:U), and the impact on confidentiality, integrity, and availability is high (C:H/I:H/A:H). This means an attacker could potentially execute arbitrary code, access sensitive data, or disrupt service availability. The plugin is commonly used to provide multilingual support on websites, often in CMS environments. While no public exploits are known yet, the nature of the vulnerability and its high CVSS score indicate a serious risk. The vulnerability was reserved in early September 2025 and published in November 2025, but no patches or mitigations have been officially released at the time of this report.

For European organizations, the impact of this vulnerability can be severe. Many European companies rely on multilingual websites to serve diverse populations and international customers, often using plugins like Falang multilanguage. Exploitation could lead to unauthorized data access, including personal data protected under GDPR, resulting in regulatory fines and reputational damage. Additionally, attackers could execute arbitrary code on web servers, leading to full system compromise, data destruction, or use of the compromised infrastructure for further attacks such as ransomware or lateral movement within networks. Availability disruptions could affect e-commerce platforms, government portals, or critical services, causing operational and financial losses. The requirement for user interaction may limit automated exploitation but does not eliminate risk, especially in phishing or social engineering scenarios common in targeted attacks. The lack of known exploits currently provides a window for proactive defense but also means organizations must act swiftly once patches are available.

Organizations should immediately inventory their use of the Falang multilanguage plugin and identify affected versions (<=1.3.65). Although no official patches are currently available, they should monitor vendor channels and security advisories for updates and apply patches promptly upon release. In the interim, restrict or disable deserialization functionality where possible, especially for inputs originating from untrusted sources. Implement web application firewalls (WAFs) with rules targeting deserialization attack patterns and monitor logs for suspicious deserialization payloads or unusual user interactions. Employ strict input validation and sanitization on all user-supplied data. Educate users about phishing risks to reduce the likelihood of successful user interaction exploitation. Consider isolating or sandboxing the affected plugin environment to limit potential damage. Finally, conduct penetration testing and vulnerability scanning focused on deserialization issues to detect potential exploitation attempts.