CVE-2019-11231: An issue was discovered in GetSimple CMS through 3.3.15.

An issue was discovered in GetSimple CMS through 3.3.15.

An issue was discovered in GetSimple CMS through 3.3.15. insufficient input sanitation in the theme-edit.php file allows upload of files with arbitrary content (PHP code, for example). This vulnerability is triggered by an authenticated user; however, authentication can be bypassed. According to the official documentation for installation step 10, an admin is required to upload all the files, including the .htaccess files, and run a health check. However, what is overlooked is that the Apache HTTP Server by default no longer enables the AllowOverride directive, leading to data/users/admin.xml password exposure. The passwords are hashed but this can be bypassed by starting with the data/other/authorization.xml API key. This allows one to target the session state, since they decided to roll their own implementation. The cookie_name is crafted information that can be leaked from the frontend (site name and version). If a someone leaks the API key and the admin username, then they can bypass authentication. To do so, they need to supply a cookie based on an SHA-1 computation of this known information. The vulnerability exists in the admin/theme-edit.php file. This file checks for forms

Description from the National Vulnerability Database, published by MITRE

What it means for a small business

If your business uses Getsimple CMS, install the vendor's update. If you're not sure whether you use it, ask whoever manages your computers.

How likely is an attack? The Exploit Prediction Scoring System, run by FIRST (the global association of security response teams), puts the odds of this one being exploited in the next 30 days at 72%, top 1% of all CVEs. That’s high: fix it ahead of everything else on the list. Scored October 28, 2026, updated daily.

Check your own setup

Website check: reads what your site runs from the outside (WordPress version, plugins it can see, old server software) and matches it against this database.
Server check: what your web server says about itself, and whether that version has known flaws.

Sources

Part of the Huttenlocher Technologies vulnerability database, refreshed twice a day from CISA and the NVD. The title, category and plain-language guidance are ours; check the linked record before acting on a detail. This is general guidance, not a review of your systems.

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