CVE-2025-31921 is a Cross-Site Request Forgery (CSRF) vulnerability identified in the WordPress plugin 'WP Ultimate Tours Builder' developed by loopus. This vulnerability affects versions up to 1.055 of the plugin. CSRF vulnerabilities allow an attacker to trick an authenticated user into submitting unwanted actions to a web application in which they are currently authenticated. In this case, the WP Ultimate Tours Builder plugin does not adequately verify the origin of requests, enabling attackers to craft malicious web requests that, when executed by an authenticated administrator or user with sufficient privileges, could alter plugin settings or perform unauthorized actions. The CVSS 3.1 base score for this vulnerability is 4.3, indicating a medium severity level. The vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N) shows that the attack can be performed remotely over the network without privileges but requires user interaction (such as clicking a malicious link). The impact is limited to integrity, with no direct confidentiality or availability effects. No known exploits are currently reported in the wild, and no patches have been linked yet. The vulnerability is categorized under CWE-352, which is a common web security weakness related to CSRF attacks. Given the nature of WordPress plugins and their widespread use, this vulnerability could be leveraged to manipulate tour-related content or configurations on affected websites if exploited.

For European organizations using WordPress websites with the WP Ultimate Tours Builder plugin, this vulnerability poses a risk primarily to the integrity of website content and configurations related to tours or travel services. Attackers could exploit this flaw to modify tour details, pricing, or booking information, potentially leading to misinformation, reputational damage, or financial loss. Although the vulnerability does not directly compromise user data confidentiality or availability of the website, the unauthorized changes could disrupt business operations or customer trust. Organizations in the travel, tourism, and hospitality sectors in Europe that rely on this plugin for their online presence are particularly at risk. Additionally, since the attack requires user interaction and an authenticated session, phishing or social engineering campaigns could be used to increase exploitation likelihood. The medium severity rating suggests a moderate risk level, but the potential for targeted attacks against high-value tourism websites in Europe warrants attention.

To mitigate this vulnerability, European organizations should first verify if their WordPress installations use the WP Ultimate Tours Builder plugin and identify the version in use. Immediate steps include: 1) Restricting administrative access to trusted users and enforcing strong authentication mechanisms such as multi-factor authentication (MFA) to reduce the risk of session hijacking or misuse. 2) Implementing web application firewalls (WAFs) with rules to detect and block suspicious CSRF attempts targeting the plugin's endpoints. 3) Educating users and administrators about phishing risks to prevent inadvertent execution of malicious requests. 4) Monitoring web server logs for unusual POST requests or changes to tour-related content that could indicate exploitation attempts. 5) Regularly checking for official patches or updates from the plugin vendor and applying them promptly once available. 6) If feasible, temporarily disabling or replacing the plugin with alternative solutions that have no known CSRF vulnerabilities until a patch is released. 7) Employing security headers such as SameSite cookies to help mitigate CSRF risks at the browser level. These measures, combined, will reduce the attack surface and limit the potential impact of this vulnerability.