# CVE-2025-66208: Configuration-Dependent RCE (OS Command Injection) in richdocumentscode proxy

> Attackers can execute arbitrary OS commands via the richdocumentscode proxy in Nextcloud environments using an intermediate reverse proxy.

- **Severity:** High 7.2 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 3 Dec 2025
- **Updated:** 3 Dec 2025

## What is CVE-2025-66208?

CVE-2025-66208 is a high-severity command injection vulnerability in CollaboraOnline online, published on 3 Dec 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Collabora Online - Built-in CODE Server (richdocumentscode) provides a built-in server with all of the document editing features of Collabora Online. In versions prior to 25.04.702, Collabora Online has a Configuration-Dependent RCE (OS Command Injection) in richdocumentscode proxy. Users of Nextcloud with Collabora Online - Built-in CODE Server app can be vulnerable to attack via proxy.php and an intermediate reverse proxy. This vulnerability is fixed in 25.04.702.

Weakness: CWE-78 (Improper Neutralization of Special Elements used in an OS Command)

## Which versions are affected by CVE-2025-66208?

It affects 1 product.


Products: Collabora Online.

## How do I fix CVE-2025-66208?

No fix has been published for CVE-2025-66208 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-66208 being exploited?

There is no known exploitation of CVE-2025-66208 in the wild and no public exploit code.

## Other vulnerabilities in CollaboraOnline online

- [CVE-2026-110447](https://insights.sbomify.com/CVE-2026-110447/): Collabora Online – Built-in CODE Server OS Command Injection (critical 9.2, exploited in the wild)
- [CVE-2021-32744](https://insights.sbomify.com/CVE-2021-32744/): Unauthenticated attacker could gain access to currently open files (critical 9.8)
- [CVE-2021-43817](https://insights.sbomify.com/CVE-2021-43817/): Reflected Cross-Site-Scripting vulnerability in Collabora Online (high 8.2)
- [CVE-2021-32745](https://insights.sbomify.com/CVE-2021-32745/): Reflected Cross-Site-Scripting vulnerability (high 7.3)
- [CVE-2024-45045](https://insights.sbomify.com/CVE-2024-45045/): JavaScript Injection via url encoded values in links in Collabora Office Android (medium 6.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-66208 and fix it if it is affected.

What it is: CVE-2025-66208 is a high-severity command injection vulnerability in CollaboraOnline online, published on 3 Dec 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-66208 in the wild and no public exploit code.

Affected product: CollaboraOnline online. 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-2025-66208/ (Markdown: https://insights.sbomify.com/CVE-2025-66208/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-66208
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-66208
- OSV: https://osv.dev/vulnerability/CVE-2025-66208

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-66208/
Summaries are generated and may contain mistakes; the official description above is the record.