Description

Author Arbitrary File Upload in Media LIbrary Assistant <= 3.39 versions.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "9.1",
  "pubDate": "2026-08-20T12:16:33.810Z",
  "pubdate": "2026-08-20T12:16:33.810Z",
  "executiveSummary": "An arbitrary file upload vulnerability exists in the Media Library Assistant plugin, specifically affecting versions 3.39 and prior. This security flaw enables authenticated users with Author-level privileges or higher to upload arbitrary files to the underlying web server through the application's media management functionality. The primary impact of this vulnerability is potential remote code execution, as an attacker can upload malicious scripts, such as PHP webshells, into the web root or accessible directories. This compromises the integrity, confidentiality, and availability of the affected WordPress installation and the host system. The risk implication is severe, as successful exploitation bypasses file type restrictions and validation mechanisms enforced by the content management system. Attacker capabilities include full system compromise if the uploaded files can be directly executed via the web server. Exploitation requirements mandate that the attacker possesses authenticated access with at least Author-level privileges within the vulnerable WordPress instance, limiting unauthenticated exploitation but posing a significant threat from malicious or compromised internal accounts.",
  "technicalDetails": "The vulnerability resides in the file handling and validation routines of the Media Library Assistant plugin for WordPress. Specifically, versions 3.39 and below fail to adequately sanitize and restrict file extensions and MIME types during the upload process handled by the plugin's internal components. The root cause is rooted in insufficient input validation and insecure file handling mechanisms, which permit users assigned the Author role to bypass intended security controls. Authentication and privilege requirements dictate that the attacker must authenticate to the WordPress administrative interface with an account holding Author-level privileges. Network exposure is standard HTTP/HTTPS, accessible wherever the WordPress application is exposed to the network. The exploitation method involves an attacker crafting a multipart HTTP POST request containing a malicious payload, typically a web shell disguised or directly formatted as an executable server-side script, submitted through the plugin's upload interface. The attack flow proceeds as follows: First, the authenticated attacker navigates to the vulnerable upload endpoint provided by the Media Library Assistant plugin. Second, the attacker uploads a file containing malicious code, bypassing the weak filtering mechanisms implemented in the vulnerable component. Third, the plugin saves the uploaded file to a public directory on the server without stripping executable permissions or enforcing strict extension whitelisting. Finally, the attacker triggers the payload by issuing an HTTP request directly to the newly uploaded file path on the server, resulting in arbitrary code execution under the security context of the web server process. The post-exploitation impact includes full system compromise, database manipulation, deployment of secondary malware, and unauthorized access to sensitive application data."
}