CVE-2026-3395 PoC — MaxSite CMS MarkItUp Preview AJAX Endpoint preview-ajax.php eval code injection

Source

https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-3395.yaml

Associated Vulnerability

Title: MaxSite CMS MarkItUp Preview AJAX Endpoint preview-ajax.php eval code injection (CVE-2026-3395)
Description:A flaw has been found in MaxSite CMS up to 109.1. This impacts the function eval of the file application/maxsite/admin/plugins/editor_markitup/preview-ajax.php of the component MarkItUp Preview AJAX Endpoint. Executing a manipulation can lead to code injection. It is possible to launch the attack remotely. The exploit has been published and may be used. Upgrading to version 109.2 will fix this issue. This patch is called 08937a3c5d672a242d68f53e9fccf8a748820ef3. You should upgrade the affected component. The code maintainer was informed beforehand about the issues. He reacted very fast and highly professional.

Description

MaxSite CMS through 109.1 allows unauthenticated remote attackers to execute arbitrary code via the MarkItUp editor preview AJAX endpoint, preview-ajax.php. The endpoint insufficiently authenticates the request, failing to ensure the user is logged in, and processes the attacker's input via unsafe usage of PHP eval() on user-supplied [php]...[/php] shortcodes. By providing a POST request to the vulnerable /ajax/ endpoint with crafted input, attackers may achieve remote code execution. The issue is addressed in version 109.2 by implementing proper authentication controls.

File Snapshot

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