IGEL OS Use of a Key Past its Expiration Date Vulnerability (CVE-2025-47827)

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.

Published Jun 5, 2025 · Updated Jun 10, 2026

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Why patchRisk explained in plain English

Worst-case scenarioIf unpatched

An attacker, without authentication, can achieve partial data exposure, complete denial of service or system unavailability. Federal agencies are required to remediate by 2025-11-04 under CISA BOD 22-01.

How the attack worksNo clicks needed

This is a Software Vulnerability (CWE-347) (CWE-347) vulnerability in IGEL IGEL OS. 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. Exploitation requires physical access, low attack complexity, no authentication required, and no user interaction required.

Am I affected?Quick check

Probably yes if any of these apply:

●IT Security

●Running igel os: v < 11.01.100; windows 10 1507: v < 10.0.10240.21161; windows 10 1607: v < 10.0.14393.8519; windows 10 1809: v < 10.0.17763.7919; windows 10 21h2: v < 10.0.19044.6456; windows 10 22h2: v < 10.0.19045.6456; windows 11 22h2: v < 10.0.22621.6060; windows 11 23h2: v < 10.0.22631.6060; windows 11 24h2: v < 10.0.26100.6899; windows 11 25h2: v < 10.0.26200.6899; windows server 2012: -, r2; windows server 2016: v < 10.0.14393.8519; windows server 2019: v < 10.0.17763.7919; windows server 2022: v < 10.0.20348.4294; windows server 2022 23h2: v < 10.0.25398.1913; windows server 2025: v < 10.0.26100.6899

Affected OS versions

Windows Server 2019Windows Server 2022Windows Server 2025Windows Server 2016Windows Server 2012 R2

Real-world incidentsWhat we've seen

Active exploitation documented in the wild. Threat-research write-up: https://github.com/Zedeldi/CVE-2025-47827

How to patch

Manual remediation steps

Apply the Vendor Patch

This vulnerability is in the CISA Known Exploited Vulnerabilities catalog — apply the vendor's security update as soon as possible.

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

References

Vendor advisory: https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2025-47827

NVD entry: https://nvd.nist.gov/vuln/detail/CVE-2025-47827

CISA KEV: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-47827

Per-OS KB reference

Per-Windows-Server-version KB mapping for this vulnerability. Each KB is the cumulative update that contains the fix for the listed OS version. Apply the KB for the OS you are running.

| Windows Server version | Cumulative update | Microsoft Update Catalog | |---|---|---| | Windows Server 2012 R2 | KB5066873 | https://catalog.update.microsoft.com/Search.aspx?q=KB5066873 | | Windows Server 2016 | KB5066836 | https://catalog.update.microsoft.com/Search.aspx?q=KB5066836 | | Windows Server 2019 | KB5066586 | https://catalog.update.microsoft.com/Search.aspx?q=KB5066586 | | Windows Server 2022 | KB5066782 | https://catalog.update.microsoft.com/Search.aspx?q=KB5066782 | | Windows Server 2025 | KB5066835 | https://catalog.update.microsoft.com/Search.aspx?q=KB5066835 |