CVE-2023-53956

CVE-2023-53956 is an authenticated file upload vulnerability in Flatnux version 2021-03.25, specifically within its file manager component. This flaw allows administrative users to upload arbitrary PHP files directly to the web root directory. Successful exploitation enables attackers to deploy malicious PHP scripts, resulting in remote code execution (RCE) on the affected server. The vulnerability is rated with a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) and is associated with CWE-434 (Unrestricted Upload of File with Dangerous Type).

Attackers require administrative credentials to exploit this vulnerability, which has network accessibility, low attack complexity, and no user interaction. Once authenticated as an admin, an attacker can leverage the file manager to upload a malicious PHP file to the web root, subsequently executing arbitrary code on the server. This grants high-impact confidentiality, integrity, and availability compromises, potentially allowing full server takeover.

Advisories and references, including those from Vulncheck and a proof-of-concept on Exploit-DB, detail the vulnerability and exploitation steps. The official Flatnux site is also referenced, though no specific patches or mitigation guidance is outlined in the available information. Security practitioners should restrict admin access and monitor file uploads in affected Flatnux deployments.