An OS command injection flaw in baserCMS’s update functionality permits an authenticated administrator to run arbitrary operating‑system commands on the web server. This flaw effectively grants the attacker the same privileges as the web application user, allowing full compromise of confidentiality, integrity, and availability of the underlying system.

The vulnerability exists in baserCMS software from all releases prior to 5.2.3, delivered by baserproject. Users deploying these older versions are affected.

The flaw has a CVSS score of 9.1 and an EPSS score of less than 1%, indicating a high severity but a relatively low probability of public exploitation. It is not listed in the CISA KEV catalog. Exploitation requires valid administrator credentials and access to the update interface; the likely attack vector involves a malicious payload supplied through the update form. Once triggered, the attacker can execute any command with the web server’s process rights.