CVE-2025-53451 is a Cross-Site Request Forgery (CSRF) vulnerability identified in the Mihdan: No External Links plugin, affecting versions up to 5.1.4. CSRF vulnerabilities occur when an attacker tricks an authenticated user into submitting a malicious request to a web application without their consent or knowledge. In this case, the Mihdan plugin, which is designed to restrict or manage external links, does not adequately verify the origin of requests that modify its settings or behavior. The vulnerability allows an attacker to craft a malicious link or webpage that, when visited by an authenticated user of a vulnerable system, could cause unintended actions such as changing plugin configurations or disabling protections. According to the CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:L), the attack can be performed remotely over the network with low attack complexity, requires no privileges, but does require user interaction (clicking a link or visiting a page). The impact affects integrity and availability, potentially allowing attackers to alter plugin settings or disrupt its functionality, but does not directly compromise confidentiality. No known exploits are reported in the wild yet, and no patches have been linked at the time of publication. The vulnerability is rated medium severity with a CVSS score of 5.4. Given the plugin’s role in controlling external links, exploitation could lead to bypassing link restrictions or enabling malicious external content, which could indirectly facilitate further attacks such as phishing or malware distribution.

For European organizations, especially those relying on WordPress sites using the Mihdan: No External Links plugin, this vulnerability poses a moderate risk. Successful exploitation could allow attackers to manipulate site behavior related to external links, potentially undermining content security policies and exposing users to malicious external sites. This could damage organizational reputation, lead to user trust erosion, and increase the risk of secondary attacks like phishing or malware infections. Organizations in sectors with high regulatory scrutiny (e.g., finance, healthcare, public sector) may face compliance challenges if such vulnerabilities are exploited to facilitate data breaches or service disruptions. Additionally, availability impacts could affect website uptime or functionality, harming business operations and customer experience. Since the attack requires user interaction, social engineering campaigns targeting employees or customers could be used to trigger the exploit, increasing the threat surface.

To mitigate this CSRF vulnerability, European organizations should: 1) Immediately check for updates or patches from the Mihdan plugin developers and apply them as soon as they become available. 2) Implement additional CSRF protections at the web application firewall (WAF) level, such as enforcing strict origin and referer header checks for requests that modify plugin settings. 3) Employ Content Security Policy (CSP) headers to restrict the domains from which scripts and forms can be submitted, reducing the risk of malicious request injection. 4) Educate users and administrators about the risks of clicking untrusted links, especially when logged into administrative interfaces. 5) Regularly audit and monitor web server logs for unusual POST requests or changes to plugin configurations that could indicate exploitation attempts. 6) Consider temporarily disabling or replacing the Mihdan plugin with alternative solutions that have verified CSRF protections until a patch is available. 7) Use multi-factor authentication (MFA) for administrative accounts to reduce the impact of compromised credentials leveraged in conjunction with CSRF attacks.