CVE-2026-54611

InstantCMS is a free and open source content management system. Versions prior to 2.18.2 have a Remote Code Execution (RCE) issue that allows remote authenticated attackers to execute any PHP code via the component installer. It is possible to upload a malicious component into the server, however, it won't be installed, but upload files will be executed. Normally all php files in upload folder are not executed, however, by uploading custom .htaccess it becomes possible. Version 2.18.2 contains a fix.

Scoring

Severity
MEDIUM
CVSS base score
5.5
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:L/A:H
EPSS probability
0.52%
CWE
CWE-94, CWE-434
Published
2026-09-08
Last modified
2026-09-09

Affected products

Weakness type

Related vulnerabilities

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