CVE-2025-9880 is a Cross-Site Request Forgery (CSRF) vulnerability affecting the Side Slide Responsive Menu plugin for WordPress, developed by dejocar. This vulnerability exists in all versions up to and including version 1.0 due to missing or incorrect nonce validation on a critical function that handles plugin settings updates. Nonce validation is a security mechanism used in WordPress to ensure that requests are intentional and originate from legitimate users. The absence or improper implementation of this validation allows unauthenticated attackers to craft malicious requests that, when executed by an authenticated site administrator (e.g., by clicking a malicious link), can modify plugin settings and inject malicious scripts into the website. This type of attack exploits the trust a web application places in the user's browser and session, enabling attackers to perform unauthorized actions without direct authentication. The vulnerability has a CVSS 3.1 base score of 6.1, indicating a medium severity level. The vector indicates that the attack can be performed remotely over the network (AV:N), requires low attack complexity (AC:L), no privileges (PR:N), but requires user interaction (UI:R). The scope is changed (S:C), meaning the vulnerability affects resources beyond the security scope of the vulnerable component. The impact affects confidentiality and integrity to a limited extent (C:L, I:L), but does not affect availability (A:N). No known exploits are currently reported in the wild, and no patches have been linked yet, suggesting that mitigation may require manual intervention or updates from the vendor once available.

For European organizations using WordPress websites with the Side Slide Responsive Menu plugin, this vulnerability poses a risk of unauthorized configuration changes and potential injection of malicious scripts. Such script injections can lead to further attacks such as session hijacking, phishing, or malware distribution targeting site visitors and administrators. The confidentiality of sensitive information managed via the website could be compromised, and the integrity of the website content and functionality could be undermined. Although availability is not directly impacted, the reputational damage and potential regulatory consequences under GDPR for data breaches or unauthorized data manipulation could be significant. Organizations with high-traffic or critical web portals are at greater risk, especially if administrators are not trained to recognize phishing attempts or suspicious links that could trigger the CSRF attack. The requirement for user interaction (administrator clicking a malicious link) somewhat limits the attack vector but does not eliminate the risk, particularly in environments where administrators access the WordPress backend frequently and may be targeted by social engineering campaigns.

1. Immediate mitigation should include educating WordPress site administrators about the risks of clicking on unsolicited or suspicious links, especially when logged into the WordPress backend. 2. Implement strict Content Security Policy (CSP) headers to limit the execution of injected scripts. 3. Use web application firewalls (WAFs) that can detect and block CSRF attack patterns or suspicious requests targeting the plugin's endpoints. 4. Restrict administrative access to the WordPress backend by IP whitelisting or VPN access to reduce exposure. 5. Monitor plugin updates closely and apply patches from the vendor as soon as they are released. 6. Consider temporarily disabling or replacing the Side Slide Responsive Menu plugin with an alternative that does not have this vulnerability until a patch is available. 7. Enable multi-factor authentication (MFA) for WordPress administrators to reduce the risk of session hijacking following a successful CSRF attack. 8. Regularly audit WordPress plugin usage and permissions to minimize the attack surface.