CriticalCVE-2018-8406

    Microsoft DirectX Graphics Kernel Privilege Escalation Vulnerability (CVE-2018-8406)

    Published In CISA KEV since Sources: CVE.org

    What is affected, what to do

    An elevation of privilege vulnerability exists when the DirectX Graphics Kernel (DXGKRNL) driver improperly handles objects in memory, aka "DirectX Graphics Kernel Elevation of Privilege Vulnerability." This affects Windows Server 2016, Windows 10, Windows 10 Servers. This CVE ID is unique from CVE-2018-8400, CVE-2018-8401, CVE-2018-8405.

    The vulnerability is being actively exploited; treat it as a priority. CISA lists it as used in ransomware campaigns. The available sources name no fixed version. Check the vendor guidance in the references below. Immediate actions, mitigation and detection rules are in the runbook below.

    Affected
    • Microsoft Windows Server 2016 eq (Server Core installation)..(Server Core installation)
    • Microsoft Windows 10 eq 32-bit Systems..32-bit Systems
    • Microsoft Windows 10 eq Version 1607 for 32-bit Systems..Version 1607 for 32-bit Systems
    • Microsoft Windows 10 eq Version 1607 for x64-based Systems..Version 1607 for x64-based Systems
    • Microsoft Windows 10 eq Version 1703 for 32-bit Systems..Version 1703 for 32-bit Systems
    • Microsoft Windows 10 eq Version 1703 for x64-based Systems..Version 1703 for x64-based Systems
    • Microsoft Windows 10 eq Version 1709 for 32-bit Systems..Version 1709 for 32-bit Systems
    • Microsoft Windows 10 eq Version 1709 for x64-based Systems..Version 1709 for x64-based Systems
    • Microsoft Windows 10 eq Version 1803 for 32-bit Systems..Version 1803 for 32-bit Systems
    • Microsoft Windows 10 eq Version 1803 for x64-based Systems..Version 1803 for x64-based Systems
    • Microsoft Windows 10 eq x64-based Systems..x64-based Systems
    • Microsoft Windows 10 Servers eq version 1709 (Server Core Installation)..version 1709 (Server Core Installation)
    • Microsoft Windows 10 Servers eq version 1803 (Server Core Installation)..version 1803 (Server Core Installation)

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    Metrics

    7.8

    Priority

    XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

    Source: NVD, CVSS v3

    7.8

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: CVE.org

    3.4 %

    EPSS score

    Moderate — model estimates 1-10% exploitation likelihood.

    Source: FIRST EPSS, percentile 89.0

    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
    227.33 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 exploited
    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
    7.8 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
    7.8
    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
    3.4 %
    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
    89.0
    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: total
    Source: CISA Vulnrichment, as of 7 February 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-404

    Response and mitigation

    Why act now?

    Prioritisation rationale

    The bug is locally exploitable with low privileges, needs no user interaction and gives full compromise of confidentiality, integrity and availability. That makes it a textbook second-stage step after phishing or initial access. CISA flags it as used in ransomware campaigns, where operators use it to gain SYSTEM before credential dumping, disabling defences and encryption. Exploitation likelihood is comparatively high for a local bug, and public exploit code has circulated for years. Residual risk is low for fleets on fully patched, supported builds. Organisations still running legacy estate (Windows 10 1507-1709, un-updated Server 2016, especially RDS/VDI) should rank it high and record it in the NIS2 risk register as technical debt with a hard upgrade deadline.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Verify patch level and deploy the security update: Microsoft fixed this vulnerability in a cumulative security update. Look up the exact KB per Windows 10 build and per Windows Server 2016 in the MSRC advisory for CVE-2018-8406. Any later cumulative update for the same build also contains the fix. Validate with Get-HotFix or your SCCM/Intune/WSUS compliance reports.
      • Identify out-of-support builds: Outside the LTSB/LTSC channel, Windows 10 1507, 1607, 1703 and 1709 are end of service. Enumerate them from CMDB or EDR inventory (OSBuild 10240, 14393, 15063, 16299) and schedule in-place upgrades to a supported build. Treat these hosts as high-risk until then.
      • Prioritise multi-user hosts: Patch RDS/terminal servers, VDI pools, Citrix workers and jump hosts on Windows Server 2016 first. On these systems, any logged-on standard user or hijacked user context can escalate to SYSTEM.
      • Contain hosts with active incidents: If an unpatched machine is already part of an incident (phishing payload, initial-access-broker activity), network-isolate it via EDR. Assume local privilege escalation has occurred.
      • Rotate credentials on affected hosts: After confirmed or suspected exploitation, reset local admin passwords (LAPS), service accounts and any cached domain credentials. SYSTEM access means LSASS was within reach.

    2. Runbook step 2

      Mitigation layers

      • Configuration/vendor workaround: Microsoft lists no workaround, and the graphics kernel driver cannot reasonably be disabled. Patching or upgrading is the only complete fix.
      • Application control (endpoint hardening): Enforce WDAC or AppLocker so that unsigned binaries and scripts cannot run from user-writable paths (%TEMP%, %APPDATA%, Downloads, C:\Users\Public). This is where LPE exploit binaries are typically dropped.
      • Defender ASR rules: Set "Block executable files unless they meet a prevalence, age, or trusted list criterion", "Block process creations originating from PSExec and WMI commands" and "Block credential stealing from LSASS" to block mode. Also enable RunAsPPL/LSA protection and Credential Guard to blunt post-escalation activity.
      • IAM/least privilege: Restrict interactive and RDP logon on servers to tiered admin groups via the "Allow log on through Remote Desktop Services" GPO. Exploitation requires local code execution, so fewer accounts with local logon rights means a smaller attack surface.
      • Network segmentation: Move unpatched legacy hosts into a dedicated VLAN. From there, allow SMB/445, RDP/3389 and WinRM/5985-5986 only to designated admin jump hosts, and route outbound internet access exclusively through a proxy.

    3. Runbook step 3

      Detection rules

      • SYSTEM processes spawned from user context (Sysmon EID 1 / Security 4688): Look for processes running as NT AUTHORITY\SYSTEM whose parent is a medium-integrity process owned by a standard user. KQL: DeviceProcessEvents | where AccountSid == "S-1-5-18" and InitiatingProcessAccountSid != "S-1-5-18" and InitiatingProcessFileName !in~ ("services.exe","svchost.exe","wininit.exe").
      • Exploit artefacts in user paths: Use Sysmon EID 11 and EID 1 to catch EXE/DLL files created in and executed from \AppData\Local\Temp\ or \Users\Public\, immediately followed by cmd.exe/powershell.exe running as SYSTEM. Sigma shape: selection_parent: ParentImage|contains: '\AppData\' + selection_user: User|contains: 'SYSTEM'.
      • Graphics kernel instability: Failed exploit attempts often bugcheck in dxgkrnl.sys. Treat System log Event ID 1001 (BugCheck) or 41 (Kernel-Power) and WER reports naming dxgkrnl.sys as suspicious, especially on servers without a GPU workload.
      • Post-exploitation chain: Shortly after the escalation, watch for service installs (System 7045 / Security 4697), LSASS access (Sysmon EID 10, TargetImage ending in lsass.exe, GrantedAccess 0x1010/0x1410), shadow-copy deletion (vssadmin delete shadows, wmic shadowcopy delete) and Defender tampering via the registry (Sysmon EID 13).
      • EDR correlation: Cross-reference "privilege escalation" or "exploit for vulnerability" alerts on Windows 10 1507-1709 and Server 2016 hosts against patch state. Escalate any hit on an unpatched system to P1.

    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

    An elevation of privilege vulnerability exists when the DirectX Graphics Kernel (DXGKRNL) driver improperly handles objects in memory, aka "DirectX Graphics Kernel Elevation of Privilege Vulnerability." This affects Windows Server 2016, Windows 10, Windows 10 Servers. This CVE ID is unique from CVE-2018-8400, CVE-2018-8401, CVE-2018-8405.

    Source: NVD (NIST), cvelistv5, CISA KEV Catalog

    Affected products

    The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

    Affected products
    Affected versionsFixed in
    MicrosoftWindows 10
    • 32-bit Systems
    • Version 1803 for 32-bit Systems
    • x64-based Systems
    • Version 1703 for 32-bit Systems
    • Version 1709 for 32-bit Systems
    • Version 1803 for x64-based Systems
    • Version 1607 for 32-bit Systems
    • Version 1703 for x64-based Systems
    • Version 1709 for x64-based Systems
    • Version 1607 for x64-based Systems
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    • —
    MicrosoftWindows 10 Servers
    • version 1803 (Server Core Installation)
    • version 1709 (Server Core Installation)
    • —
    • —
    MicrosoftWindows Server 2016
    • (Server Core installation)
    • —

    Vendors and products

    Affected operating systems

    Affected operating systems
    Windowsmicrosoftwindows_10_1507—
    Windowsmicrosoftwindows_10_1607—
    Windowsmicrosoftwindows_10_1703—
    Windowsmicrosoftwindows_10_1709—
    Windowsmicrosoftwindows_10_1803—
    Windowsmicrosoftwindows_server_1709—
    Windowsmicrosoftwindows_server_1803—
    Windowsmicrosoftwindows_server_2016—

    Weakness classes (CWE)

    • CWE-404Improper Resource Shutdown or Release

      Class

      The product does not release or incorrectly releases a resource before it is made available for re-use.

      Entry at MITRE CWE-404

    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.

    Public exploit references
    CISA KEV CatalogCISA Known Exploited Vulnerability (opens in a new tab)cisa.govactively exploited

    References & sources

    • securityfocus.com105012Vulnerability database, x_refsource_BID, Broken link, Third-party advisory, Vulnerability database
    • securitytracker.com1041461Vulnerability database, x_refsource_SECTRACK, Broken link, Third-party advisory, Vulnerability database
    • portal.msrc.microsoft.comen-US/security-guidance/advisory/CVE-2018-8406x_refsource_CONFIRM, Patch, Vendor advisory
    • cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2018-8406government-resource, US government resource
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