CVE-2026-54611 InstantCMS has Remote Code Execution in package installer
Authenticated attackers can achieve remote code execution in InstantCMS by uploading malicious components and custom .htaccess files to bypass execution restrictions.
- Exploited in the wild
- Not known
- Login needed
- An administrator
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-54611?
CVE-2026-54611 is a medium-severity vulnerability in instantsoft icms2, published on 8 Sep 2026. An attacker needs administrator access to exploit it, with no action from the victim.
Official 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.
Which versions are affected by CVE-2026-54611?
How do I fix CVE-2026-54611?
No fix has been published for CVE-2026-54611 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-54611 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-54611 exists.
Sources
Also known as GHSA-vvgv-h28h-p2m5.