# CVE-2025-54366: FreeScout's deserialization of untrusted data leads to Remote Code Execution

> Authenticated attackers with APP_KEY can achieve remote code execution via unsafe deserialization in FreeScout help desk.

- **Severity:** High 8.6 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 26 Jul 2025
- **Updated:** 28 Jul 2025
- **Also known as:** GHSA-vcc2-6r66-gvvj

## What is CVE-2025-54366?

CVE-2025-54366 is a high-severity unsafe deserialization vulnerability in freescout-help-desk freescout, published on 26 Jul 2025. An attacker needs administrator access to exploit it, with no action from the victim.

### Official description

FreeScout is a lightweight free open source help desk and shared inbox built with PHP (Laravel framework). In versions 1.8.185 and below, there is a critical deserialization vulnerability in the /conversation/ajax endpoint that allows authenticated users with knowledge of the APP_KEY to achieve remote code execution. The vulnerability occurs when the application processes the attachments_all and attachments POST parameters through the insecure Helper::decrypt() function, which performs unsafe deserialization of user-controlled data without proper validation. This flaw enables attackers to create arbitrary objects and manipulate their properties, leading to complete compromise of the web application. This is fixed in version 1.8.186.

Weakness: CWE-502 (Deserialization of Untrusted Data)

## Which versions are affected by CVE-2025-54366?

It affects 1 product.


Products: Freescout Freescout.

## How do I fix CVE-2025-54366?

No fix has been published for CVE-2025-54366 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-54366 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-54366 exists.

## Other vulnerabilities in freescout-help-desk freescout

- [CVE-2026-28289](https://insights.sbomify.com/CVE-2026-28289/): FreeScout 1.8.206 Patch Bypass for CVE-2026-27636 via Zero-Width Space Character Leads to Remote Code Execution (critical 10.0)
- [CVE-2026-27637](https://insights.sbomify.com/CVE-2026-27637/): FreeScout's Predictable Authentication Token Enables Account Takeover (critical 9.8)
- [CVE-2026-32754](https://insights.sbomify.com/CVE-2026-32754/): FreeScout: Stored XSS via Unescaped Email Template Rendering ({!! $thread->body !!}) (critical 9.3)
- [CVE-2024-29185](https://insights.sbomify.com/CVE-2024-29185/): FreeScout OS Command Injection vulnerability (critical 9.1)
- [CVE-2026-40498](https://insights.sbomify.com/CVE-2026-40498/): FreeScout has Authentication Bypass and Information Disclosure in SystemController via /system/cron (high 8.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-54366 and fix it if it is affected.

What it is: CVE-2025-54366 is a high-severity unsafe deserialization vulnerability in freescout-help-desk freescout, published on 26 Jul 2025. An attacker needs administrator access to exploit it, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-54366 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-2025-54366/ (Markdown: https://insights.sbomify.com/CVE-2025-54366/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-54366
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-54366
- OSV: https://osv.dev/vulnerability/CVE-2025-54366

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-54366/
Summaries are generated and may contain mistakes; the official description above is the record.