The vulnerability was reported by ThaiCERT as a zero-day targeting websites across the country.
Vulnerable component: Atomymaxsite
CVSSv3 score: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:F/RL:O/RC:C
CWE-ID: CWE-434 - Unrestricted Upload of File with Dangerous Type
The vulnerability allows a remote attacker to cause arbitrary code execution on the original server.
The weakness exists due to improper validation of file extensions in "index.php" script when uploading files. A remote attacker can upload arbitrary file with .php extension and execute it on the system with privileges of the web server.
Successful exploitation of the vulnerability may allow an attacker to compromise vulnerable system.
Note: the vulnerability was being actively exploited.