CVE-2025-9260 is a medium-severity vulnerability affecting the WordPress plugin "Fluent Forms – Customizable Contact Forms, Survey, Quiz, & Conversational Form Builder" developed by techjewel. The vulnerability arises from unsafe deserialization of untrusted data (CWE-502) in the plugin's parseUserProperties function. Specifically, versions from 5.1.16 up to 6.1.1 allow authenticated users with Subscriber-level privileges or higher to inject malicious PHP objects via crafted input. This PHP Object Injection can be leveraged to read arbitrary files on the server through a Property Oriented Programming (POP) chain. Furthermore, if the server configuration has allow_url_include enabled—a risky setting that allows including remote files—this vulnerability can escalate to remote code execution (RCE). The vendor attempted a patch in version 6.1.0, but it introduced a fatal error due to a missing class import, making version 6.1.2 the first fully patched and stable release. The CVSS v3.1 base score is 6.5, reflecting a medium severity with network attack vector, low attack complexity, requiring privileges but no user interaction, and impacting confidentiality but not integrity or availability. No known exploits are currently reported in the wild. This vulnerability is significant because it allows relatively low-privileged authenticated users to potentially access sensitive files or execute code remotely under certain configurations, which could compromise the hosting WordPress environment and underlying server.

For European organizations using WordPress sites with the vulnerable Fluent Forms plugin, this vulnerability poses a tangible risk to data confidentiality and system security. Attackers with subscriber-level access—often easy to obtain via registration or compromised credentials—could exploit this flaw to read sensitive files such as configuration files, database credentials, or other private data stored on the server. In environments where allow_url_include is enabled, which is uncommon but still present in some legacy or misconfigured servers, attackers could achieve remote code execution, leading to full server compromise. This could result in data breaches, defacement, or use of the server as a pivot point for further attacks. European organizations in sectors with strict data protection regulations (e.g., GDPR) face compliance risks and potential financial penalties if sensitive personal data is exposed. Additionally, the reputational damage from a public breach could be significant. Since WordPress is widely used across Europe for business, government, and non-profit websites, the vulnerability's impact could be broad, especially for organizations that have not promptly updated to the patched version 6.1.2 or later.

European organizations should immediately verify the version of Fluent Forms installed on their WordPress sites and upgrade to version 6.1.2 or later, which contains the complete and stable patch for this vulnerability. Given the patch issues in 6.1.0, versions between 6.1.0 and 6.1.1 should be considered vulnerable. Additionally, organizations should audit server PHP configurations to ensure allow_url_include is disabled, as enabling this setting significantly increases risk. Access controls should be reviewed to limit Subscriber-level privileges and monitor for suspicious account activity. Implementing Web Application Firewalls (WAFs) with rules to detect and block suspicious deserialization payloads or unusual POST requests targeting the plugin endpoints can provide an additional layer of defense. Regular security scanning and monitoring for anomalous file access or code execution attempts should be established. Finally, organizations should maintain a robust patch management process to promptly apply security updates for WordPress plugins and core software.