# CVE-2026-63190: FearlessCMS: Unauthenticated debug scripts expose filesystem operations and XSS


- **Severity:** Critical 9.4 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L`)
- **Exploited in the wild:** Not known
- **Fix available:** No
- **Published:** 28 Oct 2026
- **Updated:** 29 Oct 2026
- **Also known as:** GHSA-3mq8-hrhf-7hv6

## What is CVE-2026-63190?

CVE-2026-63190 is a critical vulnerability in fearlessgeekmedia FearlessCMS, published on 28 Oct 2026. 

### Official 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.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation), CWE-306 (Missing Authentication for Critical Functionality), CWE-288 (Authentication Bypass Using an Alternate Path or Channel), CWE-22 (Improper Limitation of a Pathname to a Restricted Directory), CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor)

## Which versions are affected by CVE-2026-63190?


## How do I fix CVE-2026-63190?

No fix has been published for CVE-2026-63190 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-63190 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-63190 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-63190 and fix it if it is affected.

What it is: CVE-2026-63190 is a critical vulnerability in fearlessgeekmedia FearlessCMS, published on 28 Oct 2026. 
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-63190 exists.

Affected product: fearlessgeekmedia FearlessCMS. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-63190/ (Markdown: https://insights.sbomify.com/CVE-2026-63190/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-63190
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-63190
- OSV: https://osv.dev/vulnerability/CVE-2026-63190

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-63190/
Summaries are generated and may contain mistakes; the official description above is the record.