CVE-2025-64639 identifies a missing authorization vulnerability in the WP Compress for MainWP plugin, a WordPress extension designed to optimize images and manage multiple WordPress sites via the MainWP dashboard. The vulnerability arises from incorrectly configured access control mechanisms, allowing unauthenticated remote attackers to bypass authorization checks. This flaw enables attackers to perform actions that should require elevated privileges, potentially modifying plugin settings or other data, thereby impacting the integrity of the managed WordPress sites. The vulnerability affects all versions up to and including 6.50.07. The CVSS v3.1 score is 5.3 (medium), reflecting that the attack vector is network-based, with low attack complexity, no privileges required, and no user interaction needed. The impact is limited to integrity, with no confidentiality or availability effects reported. No known exploits have been observed in the wild as of the publication date. The vulnerability was reserved in early November 2025 and published mid-December 2025. The lack of patch links suggests that fixes may be pending or not yet publicly available. The vulnerability is significant because MainWP is widely used by agencies and administrators to manage multiple WordPress sites, and WP Compress is a popular plugin for image optimization, making this a potentially attractive target for attackers seeking to manipulate site content or configurations without authorization.

For European organizations, this vulnerability could lead to unauthorized modifications of WordPress site configurations or content managed via the WP Compress for MainWP plugin. This may result in defacement, insertion of malicious content, or disruption of site management workflows, undermining the integrity of web assets. While confidentiality and availability are not directly impacted, integrity breaches can erode trust, damage brand reputation, and potentially facilitate further attacks such as phishing or malware distribution. Organizations using MainWP to centrally manage multiple WordPress sites are at higher risk, as a single exploit could affect numerous sites simultaneously. Given the widespread use of WordPress in Europe, especially among SMEs and digital agencies, the vulnerability could have a broad impact if exploited. The absence of known exploits currently reduces immediate risk, but the ease of exploitation without authentication means attackers could quickly develop exploits once details are public. This risk is heightened in countries with high WordPress adoption and active digital service sectors.

Organizations should monitor WP Compress and MainWP vendor channels for official patches addressing CVE-2025-64639 and apply them promptly once available. Until patches are released, administrators should restrict access to MainWP management interfaces using IP whitelisting, VPNs, or strong authentication mechanisms to limit exposure. Implementing web application firewalls (WAFs) with custom rules to detect and block suspicious requests targeting WP Compress endpoints can reduce attack surface. Regularly audit user permissions and plugin configurations to ensure no excessive privileges are granted. Additionally, maintain comprehensive backups of WordPress sites and configurations to enable rapid recovery in case of compromise. Security teams should monitor logs for unusual activity related to WP Compress or MainWP plugins. Educating site administrators about the risks of unauthorized access and encouraging minimal plugin usage can further reduce attack vectors. Finally, consider isolating management tools from public internet access where feasible.