IGEL OS: security bypass flaw under attack

What is affected

IGEL OS is mostly run by companies, schools and public bodies, not on home computers. You are unlikely to have it yourself, but organisations that hold your data may. Breaches that start with flaws like this one are how personal data ends up leaked.

IGEL OS contains a use of a key past its expiration date vulnerability that allows for Secure Boot bypass. The igel-flash-driver module improperly verifies a cryptographic signature. Ultimately, a crafted root filesystem can be mounted from an unverified SquashFS image.

What an attacker can do

This is a security bypass flaw. It lets an attacker slip past a built-in protection, so warnings and checks that normally stop malicious content never appear.

How it is reached

Needs physical access

Access the attacker needs

No account needed

Does the victim have to do something?

No, works without the victim doing anything

What to do

1. At home: nothing to install. Keep your own devices updated and use a different password for every service, so that a breach at one organisation does not open your other accounts.
2. If you administer IGEL OS at work: apply the vendor's fix or mitigation now and review logs for signs of compromise, because the flaw was being exploited before it was listed.
3. If the product is past its support date and no fix exists, take it off the internet or retire it.

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Vendor advisories and fixes

• msrc.microsoft.commsrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2025-47827

How urgent is it

CISA added this vulnerability to its Known Exploited Vulnerabilities catalogue on October 14, 2025, which means there is reliable evidence of attacks in the wild. US federal agencies must fix it by November 4, 2025, a deadline that has already passed. That deadline does not bind anyone else, but it shows how seriously the agency rates it.

The EPSS model estimates a 4.9% probability that this flaw will be exploited somewhere in the next 30 days. That is higher than 92% of all scored vulnerabilities.

Its CVSS severity score is 4.6 out of 10 (medium), as recorded in the US National Vulnerability Database.

Technical 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.