CVE-2024-5853 is a critical vulnerability in the Sirv Image Optimizer, Resizer and CDN WordPress plugin that allows arbitrary file uploads because the plugin fails to validate file types in the sirv_upload_file_by_chanks AJAX action. Authenticated attackers with at least Contributor privileges can exploit this to upload malicious files, potentially enabling remote code execution on the server hosting the WordPress site. The vulnerability affects all versions up to and including 7.2.6. The CVSS v3.1 base score is 9.9, reflecting network attack vector, low attack complexity, required privileges at the contributor level, no user interaction, and high impact on confidentiality, integrity, and availability.

An attacker with Contributor-level access or higher can upload arbitrary files to the server, which may lead to remote code execution. This compromises the confidentiality, integrity, and availability of the affected system. The vulnerability is critical due to the ease of exploitation and the potential for full system compromise.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, restrict Contributor-level access to trusted users only and consider disabling or removing the Sirv plugin if not essential. Monitor for updates from the vendor and apply patches promptly once released.