CVE-2025-12846 is a critical vulnerability affecting all versions up to 2.1.19 of the Blocksy Companion plugin for WordPress, developed by creativethemeshq. The flaw stems from insufficient validation of uploaded SVG files, specifically allowing files with double extensions (e.g., file.php.svg) to bypass sanitization checks. This weakness enables authenticated users with author-level privileges or higher to upload arbitrary files to the server. Because these files can contain executable code, attackers may achieve remote code execution (RCE), compromising the server's confidentiality, integrity, and availability. The vulnerability does not require user interaction beyond authentication, and the attack vector is network-based with low complexity. The CVSS 3.1 score of 8.8 reflects the high impact and ease of exploitation. Although no public exploits have been reported yet, the vulnerability poses a significant risk to WordPress sites using this plugin, especially those allowing author-level users to upload files. The lack of patch links suggests that a fix may not yet be available, increasing the urgency for mitigation. This vulnerability is categorized under CWE-434, which concerns unrestricted file upload vulnerabilities that can lead to remote code execution or other severe impacts.

For European organizations, the impact of CVE-2025-12846 can be severe. Successful exploitation could lead to full server compromise, data theft, defacement, or use of the server as a pivot point for further attacks within the network. This threatens the confidentiality of sensitive data, the integrity of website content, and the availability of web services. Organizations relying on WordPress with the Blocksy Companion plugin, especially those with multiple authors or contributors, face elevated risk. Compromised websites can damage brand reputation, lead to regulatory penalties under GDPR if personal data is exposed, and cause operational disruptions. The risk is amplified for sectors with high web presence such as e-commerce, media, and public services. Additionally, attackers could leverage compromised servers to launch attacks on other European infrastructure, increasing the broader cybersecurity risk landscape.

To mitigate CVE-2025-12846, European organizations should immediately restrict file upload permissions to trusted users only, ideally limiting author-level users from uploading files until a patch is available. Implement strict server-side validation of uploaded files, ensuring that only allowed file types are accepted and that double extensions are rejected. Employ web application firewalls (WAFs) with rules to detect and block suspicious file upload patterns, including SVG files with embedded scripts or unusual extensions. Monitor upload directories for unexpected files and conduct regular integrity checks. Disable execution permissions on upload directories to prevent execution of malicious files. Maintain up-to-date backups and prepare incident response plans for potential exploitation. Organizations should also track vendor announcements for patches and apply them promptly once released. Finally, consider alternative plugins with better security track records if immediate patching is not feasible.