IGEL OS Use of a Key Past its Expiration Date Vulnerability (CVE-2025-47827)
Published In CISA KEV since Sources: pwn.watch, CVE.org, Msrc Update Guide
What is affected, what to do
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.
The vulnerability is being actively exploited; treat it as a priority. Update Igel OS to version 11.01.100, Microsoft Windows 10 1507 to version 10.0.10240.21161, Microsoft Windows 10 1607 to version 10.0.14393.8519. Immediate actions, mitigation and detection rules are in the runbook below.
- Affected
- Igel OS
lt *..11.01.100 - Microsoft Windows 10 1507
lt *..10.0.10240.21161 - Microsoft Windows 10 1607
lt *..10.0.14393.8519 - Microsoft Windows 10 1809
lt *..10.0.17763.7919 - Microsoft Windows 10 21H2
lt *..10.0.19044.6456 - Microsoft Windows 10 22h2
lt *..10.0.19045.6456 - Microsoft Windows 11 22H2
lt *..10.0.22621.6060 - Microsoft Windows 11 23H2
lt *..10.0.22631.6060 - Microsoft Windows 11 24H2
lt *..10.0.26100.6899 - Microsoft Windows 11 25H2
lt *..10.0.26200.6899 - Microsoft Windows Server 2012
eq r2..r2 - Microsoft Windows Server 2016
lt *..10.0.14393.8519 - Microsoft Windows Server 2019
lt *..10.0.17763.7919 - Microsoft Windows Server 2022
lt *..10.0.20348.4294 - Microsoft Windows Server 2022 23h2
lt *..10.0.25398.1913 - Microsoft Windows Server 2025
lt *..10.0.26100.6899
- Igel OS
- Fixed in
- Igel OS
11.01.100 - Microsoft Windows 10 1507
10.0.10240.21161 - Microsoft Windows 10 1607
10.0.14393.8519 - Microsoft Windows 10 1809
10.0.17763.7919 - Microsoft Windows 10 21H2
10.0.19044.6456 - Microsoft Windows 10 22h2
10.0.19045.6456 - Microsoft Windows 11 22H2
10.0.22621.6060 - Microsoft Windows 11 23H2
10.0.22631.6060 - Microsoft Windows 11 24H2
10.0.26100.6899 - Microsoft Windows 11 25H2
10.0.26200.6899 - Microsoft Windows Server 2016
10.0.14393.8519 - Microsoft Windows Server 2019
10.0.17763.7919 - Microsoft Windows Server 2022
10.0.20348.4294 - Microsoft Windows Server 2022 23h2
10.0.25398.1913 - Microsoft Windows Server 2025
10.0.26100.6899
- Igel OS
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Metrics
4.6
Priority
XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.
Source: NVD, CVSS v3
4.6
CVSS v3
Severity Medium on the scale from 0 to 10.
Source: pwn.watch, CVE.org, Msrc Update Guide
4.9 %
EPSS score
Moderate — model estimates 1-10% exploitation likelihood.
Source: FIRST EPSS, percentile 92.1
Show all metrics
- Severity
- Critical
Priority (0–325)
The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?
Read in glossary- 200.15 Methodology
Exploit maturity
An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.
Read in glossary- actively exploitedSource: VulnCheck KEV (opens in a new tab) How we classify
XIEM Effective CVSS
XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.
Read in glossary- 4.6 Methodology
CVSS v3
CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.
Read in glossary- 4.6
EPSS score
The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.
Read in glossary- 4.9 %
- Moderate — model estimates 1-10% exploitation likelihood.
EPSS percentile
The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.
Read in glossary- 92.1
- Critical — this CVE ranks in the top fifth of all CVEs scored today (rank ≥ 80%).
KEV status
The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.
Read in glossary- Actively exploited
- Published
In CISA KEV since
The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.
Read in glossary- CISA assessment (SSVC)
- Exploitation: active · not automatable · Technical impact: partial
- Source: CISA Vulnrichment, as of 15 October 2025
CWE
CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.
Read in glossary- CWE-347
Response and mitigation
Why act now?
Prioritisation rationale
This flaw needs physical access, but neither authentication nor user interaction. The real risk is not the scored availability impact but the Secure Boot bypass: a Microsoft-signed IGEL boot chain becomes a launchpad for bootkits and tampered root filesystems on almost any UEFI machine that trusts the third-party CA. Exploitation likelihood is unusually high for a physical-vector bug, and CISA does not flag known ransomware use. Rank it high if you run thin-client fleets, public-facing endpoints, KRITIS control rooms or a highly mobile workforce. Data-centre-only estates with strict physical access control can handle it in the normal patch cycle, but DBX verification is mandatory regardless of whether you own any IGEL devices.
Runbook step 1
Immediate response (0-24 h)
- Upgrade IGEL endpoints: Use IGEL UMS to find every thin client running IGEL OS earlier than 11, especially end-of-life IGEL OS 10.x. Move them to at least IGEL OS 11.01.100, ideally to the current supported release (11.x/12.x). Devices that cannot be migrated should be retired or physically secured until they are replaced.
- Roll out Windows updates carrying the DBX revocation: The exposure reaches beyond IGEL hardware. Any machine that trusts the Microsoft third-party UEFI CA can boot attacker-supplied IGEL OS 10 media. Prioritise the cumulative updates that bring systems to builds 10.0.10240.21161 (1507), 10.0.14393.8519 (1607), 10.0.17763.7919 (1809) and 10.0.19044.6456 (21H2). For other builds, a patch is available from the vendor — check the vendor advisory for exact versions.
- Verify DBX actually landed: Installing the update is not enough; the revocation must be written into UEFI firmware. Spot-check with
Confirm-SecureBootUEFIandGet-SecureBootUEFI -Name dbxagainst Microsoft's guidance. Open a separate ticket for every host where the DBX write failed, which usually points to a firmware incompatibility. - Identify physically exposed assets: Inventory kiosks, reception and counter terminals, thin clients in public-facing areas, and laptops belonging to frequent travellers. Patch and harden these devices first.
- Lock firmware boot settings: On the exposed devices, disable USB and removable-media boot in UEFI and set a setup password wherever one is missing.
Runbook step 2
Mitigation layers
- Physical controls: Use cable locks, locked chassis and USB port blockers. Tighten access control to equipment rooms and workstation areas in line with ISO 27001 A.7.
- Firmware hardening: Where no third-party components are needed (Linux shims, option ROMs, PXE loaders), turn off "Allow Microsoft 3rd party UEFI CA" (Secured-core configuration). Test GPU and NIC option ROMs first to avoid bricking the boot process.
- Disk encryption with pre-boot authentication: Enforce BitLocker with TPM+PIN and PCR7 binding. A tampered boot path then triggers a recovery prompt, and data stays protected without the PIN. Apply the same approach to Linux clients with TPM-bound LUKS.
- Network admission (NAC): Enforce 802.1X with device-bound certificates so that a host booted from foreign media cannot reach production VLANs. Drop unknown clients into a quarantine VLAN.
- Device health gating: Make Intune/MDM Device Health Attestation or Measured Boot a condition for Conditional Access. Endpoints that cannot attest Secure Boot should lose access to cloud and VDI resources.
- Removable media policy: Restrict the USB mass-storage class to approved devices via GPO or EDR device control.
Runbook step 3
Detection rules
- Secure Boot state drift: Query
Confirm-SecureBootUEFIdaily through inventory scripts or EDR and alert on any change fromTruetoFalse. In MDE, filterDeviceTvmSecureConfigurationAssessmentfor Secure Boot configurations withIsCompliant == 0. - DBX servicing events: Monitor the System log for the
Microsoft-Windows-TPM-WMIprovider, which records successful and failed Secure Boot DBX updates. Confirm the exact event IDs against Microsoft's guidance. Failure events mark hosts that remain exposed. - Unplanned reboots plus BitLocker recovery: Correlate Event 41 (Kernel-Power) or 6008 (unexpected shutdown) with
Microsoft-Windows-BitLocker-APIrecovery events and a follow-up helpdesk request for a recovery key. Together these strongly indicate an attempt to boot foreign media. SPL starting point:index=wineventlog (EventCode=41 OR EventCode=6008) | join host [search source="*BitLocker*"]. - USB insertion preceding a reboot: Correlate Kernel-PnP 400/410 or DriverFrameworks-UserMode 2003 events with mass-storage hardware IDs, followed by a restart within minutes.
- IGEL side: In IGEL UMS, flag unregistered devices and firmware below 11.01.100. Also flag thin clients whose reported firmware differs from their assigned UMS baseline. In NAC logs, look for known MAC addresses presenting a different DHCP fingerprint.
- Secure Boot state drift: Query
Detection rules
No NEOSEC detection rule is available for this vulnerability yet.
Classification under NIS2 and CRA
Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.
NIS2
NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.
Read in glossary- Actively exploited: treat the vulnerability as a priority in vulnerability handling under Art. 21(2)(e) NIS2. If it is exploited in your environment, check the reporting obligation under Art. 23 (early warning within 24 hours).
CRA
The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.
Read in glossary- Since 11.09.2026, manufacturers of affected products with digital elements must report actively exploited vulnerabilities under Art. 14 CRA, with an early warning within 24 hours via ENISA's single reporting platform.
ISO/IEC 27001
ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.
Read in glossary- Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.
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.
Source: pwn.watch, NVD (NIST), Microsoft Security Update Guide, cvelistv5, CISA KEV Catalog, CVE.org (MITRE)
Vendors and products
- IGEL
- Microsoft Windows 10 1507
- Microsoft Microsoft Windows 10 1607
- Microsoft Microsoft Windows 10 1809
- Microsoft Microsoft Windows 10 21H2
- Microsoft Microsoft Windows 10 22h2
- Microsoft Microsoft Windows 11 22H2
- Microsoft Microsoft Windows 11 23H2
- Microsoft Microsoft Windows 11 24H2
- Microsoft Microsoft Windows 11 25H2
- Microsoft Microsoft Windows Server 2012
- Microsoft Microsoft Windows Server 2016
Affected operating systems
| Other | igel | igel_os | — |
| Windows | microsoft | windows_10_1507 | — |
| Windows | microsoft | windows_10_1607 | — |
| Windows | microsoft | windows_10_1809 | — |
| Windows | microsoft | windows_10_21h2 | — |
| Windows | microsoft | windows_10_22h2 | — |
| Windows | microsoft | windows_11_22h2 | — |
| Windows | microsoft | windows_11_23h2 | — |
| Windows | microsoft | windows_11_24h2 | — |
| Windows | microsoft | windows_11_25h2 | — |
| Windows | microsoft | windows_server_2012 | r2 |
| Windows | microsoft | windows_server_2012 | — |
| Windows | microsoft | windows_server_2016 | — |
| Windows | microsoft | windows_server_2019 | — |
| Windows | microsoft | windows_server_2022 | — |
| Windows | microsoft | windows_server_2022_23h2 | — |
| Windows | microsoft | windows_server_2025 | — |
Weakness classes (CWE)
CWE-347Improper Verification of Cryptographic Signature
Base
The product does not verify, or incorrectly verifies, the cryptographic signature for data.
Entry at MITRE CWE-347
Public exploit references
Publicly reported proof-of-concepts, exploit modules and detection templates for this vulnerability. NEOSEC links to the original sources only and does not provide any exploit code.
| CISA KEV Catalog | CISA Known Exploited Vulnerability (opens in a new tab)cisa.gov | actively exploited | |
| GitHub | Zedeldi/CVE-2025-47827 (opens in a new tab)github.com | PoC (publicly reported)reported, not verified | — |
References & sources
- github.comZedeldi/igelfsProduct
- github.comZedeldi/CVE-2025-47827Exploit, Third-party advisory
- Microsoft Security Update GuideIGEL advisory: IGEL OSVendor advisory, Third-party advisory, pwn-watch
- cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2025-47827government-resource, US government resource
- pwn.watchpwn.watch: IGEL OS: OS Use of a Key Past its Expiration Date Vulnerabilitypwn-watch
- NVD (NIST)NVD: CVE-2025-47827pwn-watch
- cisa.govCISA Known Exploited Vulnerabilities Catalogpwn-watch
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<a href="https://intel.neosec.eu/en/cve/CVE-2025-47827"><img src="https://intel.neosec.eu/badge/cve/CVE-2025-47827.svg?lang=en" alt="CVE-2025-47827 – NEOSEC Intel" height="20"></a>