CVE-2025-13749 is a Cross-Site Request Forgery vulnerability identified in the Clearfy Cache – WordPress optimization plugin, which provides features such as minifying HTML, CSS, and JavaScript, and deferring script loading to improve website performance. The vulnerability affects all versions up to and including 2.4.0 due to the absence of nonce validation in the wbcr_upm_change_flag function. Nonce validation is a security measure that ensures requests are legitimate and initiated by authenticated users. Without this protection, an attacker can craft a malicious request that, when executed by an authenticated administrator (e.g., by clicking a link), disables plugin or theme update notifications. This action does not require the attacker to be authenticated themselves but relies on social engineering to induce the administrator to perform the action. The CVSS v3.1 score is 4.3 (medium severity), reflecting the low complexity of attack (no privileges required, network vector), but requiring user interaction and only impacting integrity (disabling update notifications). The vulnerability does not directly lead to data disclosure or denial of service but weakens the site's security posture by preventing timely updates, which could be leveraged by other threats. No patches or exploits are currently reported, but the risk lies in the potential for attackers to maintain persistence or escalate attacks by blocking updates. This vulnerability is categorized under CWE-352 (Cross-Site Request Forgery).

For European organizations, this vulnerability primarily threatens the integrity of WordPress site maintenance processes. By disabling update notifications, attackers can prevent administrators from being alerted to critical security patches, increasing the risk of exploitation from other vulnerabilities. This is particularly concerning for organizations relying on WordPress for e-commerce, government portals, or other critical services, where delayed updates can lead to data breaches or service disruptions. Although the vulnerability itself does not directly compromise data confidentiality or availability, it creates an attack vector for more severe exploits. The impact is amplified in environments where administrators may be less aware of phishing or social engineering tactics, or where update processes are not automated. The absence of known exploits reduces immediate risk but does not eliminate the threat, especially given the widespread use of WordPress and this plugin in Europe.

1. Monitor for and apply plugin updates from the vendor as soon as they become available to address this vulnerability. 2. Until patches are released, implement Web Application Firewall (WAF) rules to detect and block suspicious CSRF attempts targeting the wbcr_upm_change_flag function or related endpoints. 3. Educate WordPress administrators about the risks of clicking unsolicited links, especially those that could trigger administrative actions. 4. Consider disabling or limiting the use of the Clearfy Cache plugin if update notification integrity is critical and no patch is available. 5. Employ multi-factor authentication (MFA) for WordPress admin accounts to reduce the risk of account compromise. 6. Regularly audit WordPress plugin and theme update statuses manually to detect any unauthorized disabling of notifications. 7. Use security plugins that provide additional CSRF protections or monitoring capabilities. 8. Encourage automation of updates where feasible to reduce reliance on notifications.