fearlessgeekmedia FearlessCMS up to 0.1.3 Debug Scripts debug_save_flow.php file_put_contents path path traversal

Summaryinfo

A vulnerability categorized as very critical has been discovered in fearlessgeekmedia FearlessCMS up to 0.1.3. Affected by this issue is the function file_put_contents of the file admin/debug_save_flow.php of the component Debug Scripts. Such manipulation of the argument path leads to path traversal. This vulnerability is listed as CVE-2026-63190. The attack may be performed from remote. There is no available exploit. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in fearlessgeekmedia FearlessCMS up to 0.1.3 and classified as very critical. Affected by this issue is the function file_put_contents of the file admin/debug_save_flow.php of the component Debug Scripts. The manipulation of the argument path with an unknown input leads to a path traversal vulnerability. Using CWE to declare the problem leads to CWE-22. The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. Impacted is confidentiality, integrity, and availability. CVE summarizes:

FearlessCMS is a flat-file `content` management system centered on simplicity and open source. Prior to version 0.1.4, five debug/test PHP scripts under `admin/` perform privileged operations without `isLoggedIn()` authentication checks, CSRF protection or adequate `path` validation. On PHP's built-in development server, including the default Docker deployment, `router.php` checks an unnormalized admin URI prefix while the filesystem resolves dot segments, so `/./admin/` bypasses the admin login gate and executes those scripts directly. In `admin/debug_save_flow.php`, attacker-controlled `path` and `content` reach `file_put_contents` for arbitrary `.md` writes under `content`/ or outside it through `path` traversal, enabling site defacement and stored JavaScript in public pages; `print_r($_POST)` output without `htmlspecialchars` escaping also causes reflected cross-site scripting. The `admin/debug_content.php` `path` parameter reaches `scandir()`, `file_get_contents()` and `posix_getpwuid()`, permitting arbitrary directory enumeration and `.md` file reads that expose absolute paths, ownership, permissions, hashes and `content` previews. The `admin/preview-handler.php` endpoint accepts JSON `content` and `title` and writes enumerable files under `content/_preview/`, enabling stored cross-site scripting and disk exhaustion. The `admin/testdebug.php` endpoint appends to `admin/testdebug.log` without authentication, also enabling disk exhaustion. The `admin/test_redirect.php` script exposes a test artifact but escapes its inputs and is not itself an XSS sink. Stored script execution can steal sessions and compromise administrators when they view affected `content`. Reads and writes execute with PHP's privileges; the tested deployment runs PHP as root, amplifying filesystem impact. This issue is fixed in version 0.1.4.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-63190 since 07/16/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 10/28/2026). This vulnerability is assigned to T1006 by the MITRE ATT&CK project.

By approaching the search of inurl:admin/debug_save_flow.php it is possible to find vulnerable targets with Google Hacking.

Upgrading to version 0.1.4 eliminates this vulnerability.

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Productinfo

Vendor

• fearlessgeekmedia

Name

• FearlessCMS

Version

• 0.1.0
• 0.1.1
• 0.1.2
• 0.1.3

Website

• Product: https://github.com/fearlessgeekmedia/FearlessCMS/

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