CVE-2025-62891 is a Cross-Site Request Forgery (CSRF) vulnerability identified in the Off-Canvas Sidebars & Menus (Slidebars) plugin by Jory Hogeveen, affecting all versions up to and including 0.5.8.5. CSRF vulnerabilities allow attackers to induce authenticated users to perform unwanted actions on a web application without their consent, by exploiting the trust a site has in the user's browser. This particular vulnerability does not require the attacker to have any privileges (PR:N) but does require user interaction (UI:R), such as clicking a malicious link or visiting a crafted webpage. The vulnerability impacts confidentiality, integrity, and availability (C:H/I:H/A:H), indicating that an attacker could potentially manipulate sensitive data, alter application state, or disrupt service availability. The attack vector is network-based (AV:N), meaning exploitation can be performed remotely over the internet. The plugin is commonly used to implement off-canvas sidebars and menus in web applications, often integrated into content management systems or custom websites. Since no patches or exploit code are currently publicly available, the risk is theoretical but significant given the high CVSS score. The vulnerability's root cause is the lack of proper anti-CSRF protections, such as missing or ineffective CSRF tokens, allowing unauthorized state-changing requests to be accepted by the server. This can lead to unauthorized configuration changes, privilege escalation, or injection of malicious content through the vulnerable plugin's interface.

For European organizations, the impact of CVE-2025-62891 can be substantial, especially for those relying on the Slidebars plugin for web interface components. Successful exploitation could lead to unauthorized changes in website navigation or content, leakage of sensitive user data, or disruption of web services, damaging organizational reputation and user trust. Since the vulnerability affects confidentiality, integrity, and availability, attackers could manipulate user sessions, inject malicious scripts, or cause denial of service conditions. This is particularly critical for sectors with strict data protection regulations such as finance, healthcare, and government services in Europe, where unauthorized data exposure or service disruption could lead to regulatory penalties under GDPR. Additionally, the ease of remote exploitation combined with no required privileges increases the attack surface, making it attractive for attackers targeting European organizations with a strong online presence. The lack of known exploits currently reduces immediate risk but does not eliminate the threat, especially as exploit code could emerge rapidly after public disclosure.

European organizations should take proactive and specific measures to mitigate this vulnerability beyond generic advice. First, they should inventory all web applications and CMS instances using the Slidebars plugin and verify the version in use. Immediate patching is critical once an official fix is released by the vendor. Until patches are available, organizations should implement web application firewall (WAF) rules to detect and block suspicious CSRF attempts targeting the plugin's endpoints. Developers should audit the plugin's code to add or enforce anti-CSRF tokens on all state-changing requests and validate the origin and referer headers where possible. User sessions should be protected with secure cookies and SameSite attributes to reduce CSRF risks. Additionally, organizations should educate users about the risks of clicking unknown links and consider implementing multi-factor authentication to reduce the impact of session hijacking. Regular security testing and monitoring for anomalous activities related to the plugin's functionality are recommended. Finally, organizations should prepare incident response plans specific to web application compromises involving CSRF attacks.