Executive brief
HAXcms is a content management system used to build and manage microsites. A security flaw in its PHP backend allows an attacker with low-level access to execute unauthorized commands on the underlying server. This could lead to a total system takeover, allowing attackers to steal sensitive data, delete files, or disrupt website operations.
Technical details
An OS command injection vulnerability exists in the Git.php library of the HAXcms PHP backend due to improper neutralization of shell metacharacters. The application constructs shell command strings by concatenating unsanitized input and executing them via proc_open(). While 17 functions invoke shell commands, only the commit() function correctly utilizes escapeshellarg(). An attacker with low-privileged access who can influence Git parameters—potentially through configuration poisoning or other vulnerabilities—can execute arbitrary OS commands with the privileges of the web server. This issue is patched in version 26.0.0.
Affected products
- HAX the Web HAXcms PHP backend < 26.0.0
Timeline
- 2026-05-12: advisory: Vendor advisory published on GitHub
- 2026-06-05: disclosed: CVE published to NVD
- 2026-06-05: patched: Version 26.0.0 released to address the vulnerability