CVE-2023-53956

HIGH 8.8

Flatnux 2021-03.25 Authenticated File Upload Remote Code Execution

CVSS Score

8.8

EPSS Score

0.0%

EPSS Percentile

0th

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.

CWE	CWE-434
Vendor	altervista
Product	flatnux
Published	Dec 19, 2025
Last Updated	Apr 7, 2026

Stay Ahead of the Next One

Get instant alerts for altervista flatnux

Be the first to know when new high vulnerabilities affecting altervista flatnux are published — delivered to Slack, Telegram or Discord.

Get Free Alerts → Free · No credit card · 60 sec setup

CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Affected Versions

altervista / flatnux

2021-03.25

References

NVD ↗ CVE.org ↗ EPSS Data ↗

exploit-db.com: https://www.exploit-db.com/exploits/51295 flatnux.altervista.org: http://flatnux.altervista.org/flatnux.html vulncheck.com: https://www.vulncheck.com/advisories/flatnux-authenticated-file-upload-remote-code-execution

Credits

Ömer Hasan Durmuş