CVE-2026-63190
Received
Received - Intake
Path Traversal and XSS in FearlessCMS Prior to 0.1.4
Vulnerability report for CVE-2026-63190, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-10-28
Last updated on: 2026-10-28
Assigner: GitHub, Inc.
Description
Description
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.
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| fearlessgeekmedia | FearlessCMS | < 0.1.4 |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| 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. |
| CWE-79 | The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. |
| CWE-200 | The product exposes sensitive information to an actor that is not explicitly authorized to have access to that information. |
| CWE-288 | The product requires authentication, but the product has an alternate path or channel that does not require authentication. |
| CWE-306 | The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources. |
