> For the complete documentation index, see [llms.txt](https://docs.sealsecurity.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.sealsecurity.io/introduction/product-family/seal-os.md).

# Seal OS

**Seal OS** remediates vulnerabilities in OS-level packages and language runtimes (Node.js, Python, JVM, and others) on your Linux servers and inside your containers. It covers the system layer that sits below your application code.

<figure><img src="/files/YfwNefcdPKZEEuj2ARzj" alt="Seal OS covers Alpine, Debian, Ubuntu, CentOS, Red Hat, RHEL, Fedora, and Amazon Linux"><figcaption><p>Seal OS covers the major Linux distributions and their package families.</p></figcaption></figure>

## What it covers

OS package ecosystems:

* **APK** (Alpine)
* **DEB** (Debian, Ubuntu)
* **RPM** (Red Hat, CentOS, RHEL, Fedora, Amazon Linux)

Open-source language runtimes installed via the OS package manager are also covered, including Node.js, Python, and the JVM.

Seal OS supports **EOL distributions**. When the upstream distribution maintainer has stopped releasing security updates, Seal continues to ship sealed package versions for the affected components.

## How it is delivered

Seal OS applies fixes via the Seal CLI, in place. The CLI runs on your Linux servers, inside your container builds, or in standalone environments, and installs sealed versions of the affected packages where they live.

## Related

* [Setting up Seal OS](/setup-apps-os/seal-os-cicd.md): day-1 setup.
* [Working with Seal OS](/using-platform/working-with-seal-os.md): the day-to-day workflow.