CVE-2025-9880 is a Cross-Site Request Forgery (CSRF) vulnerability identified in the Side Slide Responsive Menu plugin for WordPress, developed by dejocar. This vulnerability affects all versions up to and including version 1.0. The root cause is the absence or incorrect implementation of nonce validation in a critical function responsible for updating plugin settings. Nonces in WordPress are security tokens used to verify that requests are intentional and originate from legitimate users. Without proper nonce validation, an attacker can craft a malicious web request that, when executed by an authenticated administrator (e.g., by clicking a link), causes the plugin to update its settings or inject malicious scripts. This attack vector does not require the attacker to be authenticated themselves, relying instead on social engineering to trick an administrator into performing the action. The vulnerability has a CVSS 3.1 base score of 6.1, categorized as medium severity, with the vector indicating network attack vector (AV:N), low attack complexity (AC:L), no privileges required (PR:N), user interaction required (UI:R), scope changed (S:C), and impacts on confidentiality and integrity but not availability. The scope change indicates that the vulnerability affects resources beyond the initially vulnerable component, potentially impacting the entire WordPress site. Although no known exploits are currently reported in the wild, the vulnerability poses a significant risk due to the widespread use of WordPress and the plugin's ability to alter site behavior and inject malicious content. This can lead to unauthorized changes, defacement, or further exploitation through script injection.

For European organizations using WordPress sites with the Side Slide Responsive Menu plugin, this vulnerability can lead to unauthorized modification of website settings and injection of malicious scripts. This compromises the confidentiality and integrity of the website content and potentially the data of site visitors. Attackers could leverage this to conduct phishing, deliver malware, or manipulate site behavior, damaging organizational reputation and trust. In sectors such as finance, healthcare, government, and e-commerce, where data protection and service integrity are critical, such compromises can lead to regulatory penalties under GDPR, loss of customer confidence, and operational disruptions. The fact that exploitation requires only tricking an administrator into clicking a link means that social engineering attacks could be effective, increasing the risk. The scope change in the vulnerability means that the impact could extend beyond the plugin itself, potentially affecting other parts of the WordPress installation and associated data. Given WordPress's popularity in Europe for business and governmental websites, the threat is relevant and warrants prompt attention.

1. Immediate action should be to update the Side Slide Responsive Menu plugin to a patched version once released by the vendor. Until then, consider disabling the plugin if feasible. 2. Implement strict administrative access controls and limit the number of users with plugin configuration privileges to reduce exposure. 3. Educate administrators about the risks of clicking on unsolicited or suspicious links, especially those received via email or messaging platforms. 4. Employ Web Application Firewalls (WAFs) with rules to detect and block CSRF attack patterns targeting WordPress admin endpoints. 5. Monitor logs for unusual POST requests to plugin-related endpoints, especially those originating from external referrers or unusual sources. 6. Use security plugins that enforce nonce validation and additional CSRF protections at the WordPress level. 7. Regularly audit and harden WordPress installations, including disabling unused plugins and themes to reduce attack surface. 8. Consider implementing Content Security Policy (CSP) headers to mitigate the impact of injected scripts. These steps go beyond generic advice by focusing on administrative behavior, monitoring, and layered defenses specific to WordPress and this plugin.