# CVE-2026-53593: File upload in freescout

> Authenticated attackers can upload .pht web shells to execute arbitrary commands due to an incomplete file extension denylist.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 20 Jul 2026
- **Updated:** 21 Jul 2026
- **Also known as:** GHSA-27vp-fpg8-j8wv

## What is CVE-2026-53593?

CVE-2026-53593 is a high-severity vulnerability in freescout-help-desk freescout, published on 20 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

FreeScout is a free help desk and shared inbox built with PHP's Laravel framework. Prior to version 1.8.224, the denylist that neutralizes dangerous file uploads (`Helper::$restricted_extensions`) is incomplete: it does not cover the `.pht` extension. The authenticated upload endpoint `POST /uploads/upload` (`SecureController@upload`) stores files with their original extension into the web-accessible directory `storage/app/public/uploads/` (served at `/storage/uploads/`). On the standard Apache + `libapache2-mod-php` deployment, the default handler `<FilesMatch ".+\.ph(ar|p[3457]?|t|tml)$">` executes `.pht`, so **any authenticated agent can upload a `.pht` web shell and run arbitrary commands as the web-server user** (`www-data`). This is a direct bypass of the fix for CVE-2025-48471, which added `phtml`/`phar` but not `pht` (nor `phtm`, `phps`). Version 1.8.224 contains an updated fix.

Weakness: CWE-434 (Unrestricted Upload of File with Dangerous Type)

## Which versions are affected by CVE-2026-53593?


## How do I fix CVE-2026-53593?

No fix has been published for CVE-2026-53593 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-53593 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-53593 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-53593 and fix it if it is affected.

What it is: CVE-2026-53593 is a high-severity vulnerability in freescout-help-desk freescout, published on 20 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-53593 exists.

Affected product: freescout-help-desk freescout. 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-2026-53593/ (Markdown: https://insights.sbomify.com/CVE-2026-53593/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53593
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53593
- OSV: https://osv.dev/vulnerability/CVE-2026-53593

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53593/
Summaries are generated and may contain mistakes; the official description above is the record.