Vulnerability · Published Dec 19, 2025 · Assigned by VulnCheck
CVE-2023-53956Flatnux 2021-03.25 Authenticated File Upload Remote Code Execution
High 8.8
In plain English
A high-severity unrestricted file upload in flatnux from altervista. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.8% (higher than 56% of all known vulnerabilities).
Severity (CVSS 3.1)8.8High
Exploit odds (30 days)0.8%top 44.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known
Official description
Flatnux 2021-03.25 contains an authenticated file upload vulnerability that allows administrative users to upload arbitrary PHP files through the file manager. Attackers with admin credentials can upload malicious PHP scripts to the web root directory, enabling remote code execution on the server.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| altervista | flatnux | 2021-03.25 |
Weakness: CWE-434 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
References
- ExploitDB-51295 exploit
- Official Product Homepage product
- VulnCheck Advisory: Flatnux 2021-03.25 Authenticated File Upload Remote Code Execution third-party-advisory