CVE-2026-54611: CWE-94: Improper Control of Generation of Code ('Code Injection') in instantsoft icms2
Description
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.
CVSS v3.1
Score 5.5medium
Affected software
instantsoft
icms2
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AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-54611 describes a remote code execution vulnerability in InstantCMS (icms2) versions before 2.18.2. The flaw allows remote authenticated attackers to upload malicious PHP files through the component installer. Although PHP files are normally not executed in the upload folder, attackers can upload a custom .htaccess file to override this behavior and execute arbitrary PHP code. This vulnerability is classified under CWE-94 (Improper Control of Generation of Code) and CWE-434 (Unrestricted Upload of File with Dangerous Type). The issue is fixed in version 2.18.2.
Potential Impact
An authenticated attacker can execute arbitrary PHP code on the server, potentially leading to full system compromise or denial of service. The vulnerability requires authentication but allows code execution, which can severely impact the confidentiality, integrity, and availability of the affected system.
Mitigation Recommendations
Upgrade InstantCMS to version 2.18.2 or later, which contains the fix for this vulnerability. Until then, restrict access to the component installer to trusted users only and monitor for unauthorized file uploads. Patch status is not explicitly confirmed in the vendor advisory, but the description states version 2.18.2 contains a fix.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-15T19:45:23.540Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6aa044c4acd9273b49fa5fb3
Added to database: 09/08/2026, 17:24:20 UTC
Last enriched: 09/09/2026, 10:22:37 UTC
Last updated: 10/21/2026, 13:20:22 UTC
Views: 40
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