CVE-2025-4105 is a security vulnerability identified in the Splitit plugin for WordPress, specifically affecting all versions up to and including 4.2.8. The vulnerability stems from missing authorization checks in the 'splitIt-flexfields-payment-gateway.php' file, which allows authenticated users with Subscriber-level access or higher to modify plugin settings without proper permission validation. This flaw is categorized under CWE-862 (Missing Authorization), indicating that the plugin does not adequately verify whether a user is authorized to perform certain actions. Exploiting this vulnerability, an attacker with minimal privileges can alter critical plugin configurations, such as switching the payment environment between sandbox and production modes. This could lead to unauthorized manipulation of payment processing behavior, potentially enabling fraudulent transactions or disruption of legitimate payment flows. The vulnerability has a CVSS 3.1 base score of 5.4, reflecting a medium severity level. The attack vector is network-based (remote), requires low attack complexity, and only requires privileges equivalent to a subscriber role, with no user interaction needed. The impact primarily affects confidentiality and integrity, as unauthorized changes to payment settings could expose sensitive data or corrupt transaction processing. No known public exploits have been reported to date, and no official patches have been linked yet, indicating the need for vigilance and proactive mitigation by affected users.

For European organizations using WordPress websites with the Splitit plugin, this vulnerability poses a significant risk to the integrity and confidentiality of payment processing systems. Unauthorized modification of plugin settings could lead to financial fraud, data leakage, or disruption of e-commerce operations. Given the widespread use of WordPress in Europe and the popularity of Splitit as a payment installment solution, especially among small to medium-sized enterprises (SMEs) in retail and services sectors, the threat could affect a broad range of businesses. The ability for low-privilege users to escalate their influence over payment configurations increases the risk of insider threats or exploitation of compromised accounts. Additionally, regulatory frameworks such as GDPR impose strict requirements on data protection and breach notification, so exploitation of this vulnerability could result in legal and reputational consequences for European companies. The lack of user interaction and low complexity of exploitation further heighten the risk, making it easier for attackers to leverage this vulnerability in automated or targeted attacks.

To mitigate this vulnerability, European organizations should immediately audit user roles and permissions on WordPress sites using the Splitit plugin, ensuring that Subscriber-level accounts are strictly controlled and monitored. Restricting the number of users with even minimal privileges can reduce the attack surface. Until an official patch is released, organizations should consider temporarily disabling the Splitit plugin or switching to alternative payment solutions if feasible. Implementing Web Application Firewalls (WAFs) with custom rules to detect and block unauthorized requests targeting the 'splitIt-flexfields-payment-gateway.php' endpoints can provide additional protection. Regularly monitoring plugin configuration changes and enabling logging for administrative actions will help detect suspicious activity early. Organizations should also keep abreast of updates from Splitit and WordPress security advisories to apply patches promptly once available. Finally, enforcing strong authentication mechanisms and multi-factor authentication (MFA) for all WordPress accounts can help prevent unauthorized access that could lead to exploitation.