CriticalCVE-2019-0752

    Microsoft Internet Explorer Type Confusion Vulnerability (CVE-2019-0752)

    Published In CISA KEV since Sources: CVE.org

    What is affected, what to do

    A remote code execution vulnerability exists in the way that the scripting engine handles objects in memory in Internet Explorer, aka 'Scripting Engine Memory Corruption Vulnerability'. This CVE ID is unique from CVE-2019-0739, CVE-2019-0753, CVE-2019-0862.

    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 Internet Explorer 11 eq Windows 7 for 32-bit Systems Service Pack 1..Windows 7 for 32-bit Systems Service Pack 1
    • Microsoft Internet Explorer 11 eq Windows 7 for x64-based Systems Service Pack 1..Windows 7 for x64-based Systems Service Pack 1
    • Microsoft Internet Explorer 11 eq Windows Server 2008 R2 for x64-based Systems Service Pack 1..Windows Server 2008 R2 for x64-based Systems Service Pack 1
    • Microsoft Internet Explorer 11 eq Windows 8.1 for 32-bit systems..Windows 8.1 for 32-bit systems
    • Microsoft Internet Explorer 11 eq Windows 8.1 for x64-based systems..Windows 8.1 for x64-based systems
    • Microsoft Internet Explorer 11 eq Windows Server 2012 R2..Windows Server 2012 R2
    • Microsoft Internet Explorer 11 eq Windows RT 8.1..Windows RT 8.1
    • Microsoft Internet Explorer 11 eq Windows 10 for 32-bit Systems..Windows 10 for 32-bit Systems
    • Microsoft Internet Explorer 11 eq Windows 10 for x64-based Systems..Windows 10 for x64-based Systems
    • Microsoft Internet Explorer 11 eq Windows Server 2016..Windows Server 2016
    • Microsoft Internet Explorer 11 eq Windows 10 Version 1607 for 32-bit Systems..Windows 10 Version 1607 for 32-bit Systems
    • Microsoft Internet Explorer 11 eq Windows 10 Version 1607 for x64-based Systems..Windows 10 Version 1607 for x64-based Systems
    • Microsoft Internet Explorer 11 eq Windows 10 Version 1703 for 32-bit Systems..Windows 10 Version 1703 for 32-bit Systems
    • Microsoft Internet Explorer 11 eq Windows 10 Version 1703 for x64-based Systems..Windows 10 Version 1703 for x64-based Systems
    • Microsoft Internet Explorer 11 eq Windows 10 Version 1709 for 32-bit Systems..Windows 10 Version 1709 for 32-bit Systems
    • Microsoft Internet Explorer 11 eq Windows 10 Version 1709 for x64-based Systems..Windows 10 Version 1709 for x64-based Systems
    • Microsoft Internet Explorer 11 eq Windows 10 Version 1803 for 32-bit Systems..Windows 10 Version 1803 for 32-bit Systems
    • Microsoft Internet Explorer 11 eq Windows 10 Version 1803 for x64-based Systems..Windows 10 Version 1803 for x64-based Systems
    • Microsoft Internet Explorer 11 eq Windows 10 Version 1803 for ARM64-based Systems..Windows 10 Version 1803 for ARM64-based Systems
    • Microsoft Internet Explorer 11 eq Windows 10 Version 1809 for 32-bit Systems..Windows 10 Version 1809 for 32-bit Systems
    • Microsoft Internet Explorer 11 eq Windows 10 Version 1809 for x64-based Systems..Windows 10 Version 1809 for x64-based Systems
    • Microsoft Internet Explorer 11 eq Windows 10 Version 1809 for ARM64-based Systems..Windows 10 Version 1809 for ARM64-based Systems
    • Microsoft Internet Explorer 11 eq Windows Server 2019..Windows Server 2019
    • Microsoft Internet Explorer 11 eq Windows 10 Version 1709 for ARM64-based Systems..Windows 10 Version 1709 for ARM64-based Systems
    • Microsoft Internet Explorer 10 eq Windows Server 2012..Windows Server 2012

    Not sure whether and how you are affected? Ask a question about this vulnerability

    Metrics

    7.5

    Priority

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

    Source: NVD, CVSS v3

    7.5

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: CVE.org

    81.7 %

    EPSS score

    High — model estimates ≥ 50% chance of real-world exploitation within 30 days.

    Source: FIRST EPSS, percentile 99.64

    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
    241.93 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
    7.5 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
    7.5
    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
    81.7 %
    High — model estimates ≥ 50% chance of real-world exploitation within 30 days.
    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
    99.64
    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 14 February 2022
    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-843

    Response and mitigation

    Why act now?

    Prioritisation rationale

    This flaw gives an attacker remote code execution over the network without authentication. All it needs is for a user to open a crafted web page or document. The high attack complexity rating does little to slow real-world attackers, because exploit kits and malvertising deliver the exploit automatically. Its exploitation likelihood ranks among the highest of any CVE, and CISA flags known use in ransomware campaigns. Your score should hinge on residual IE exposure: treat this as critical if you run legacy hosts, OT engineering workstations, terminal servers or line-of-business apps that depend on IE. Fully patched estates with IE disabled carry low residual risk, but should evidence that with inventory data for NIS2 documentation.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Close the patch gap: Deploy the Internet Explorer cumulative security update from Microsoft's April 2019 release, or any later cumulative IE/Windows update, to all clients, terminal servers and VDI golden images. Look up the per-OS KB number in the Microsoft Security Update Guide entry for CVE-2019-0752. Updates are cumulative, so any current patch level remediates this flaw.
      • Find legacy hosts: Use SCCM/Intune or Defender Vulnerability Management to identify every host where iexplore.exe can still run or that has stopped receiving cumulative updates. Pay particular attention to Windows 7, Server 2008 R2 and out-of-support LTSC builds. Patch these first or cut their internet access.
      • Disable IE as a browser: Enable the GPO "Disable Internet Explorer 11 as a standalone browser" and redirect users to Microsoft Edge. IE11 is retired on Windows 10/11 and should not be launchable at all.
      • Kill VBScript in the browser: Set "Allow VBScript to run in Internet Explorer" to Disabled for the Internet and Restricted Sites zones (registry Zones\3\140C = 3). This is the default from Windows 10 1809 onward, but enforce it explicitly.
      • If compromise is suspected: Isolate the host via EDR, reset the user's credentials and hunt for ransomware precursors (Cobalt Strike beacons, loaders, scheduled tasks).

    2. Runbook step 2

      Mitigation layers

      • Network/proxy: Log outbound HTTP/HTTPS traffic carrying an MSIE/Trident/7.0 user agent at the web proxy. Block it for any destination outside an allowlist of documented legacy intranet apps. Also block the "malvertising" and "newly registered domains" categories.
      • IPS/secure web gateway: Enable exploit-kit landing-page and IE scripting-engine signatures (Suricata ET EXPLOIT_KIT and WEB_CLIENT categories). Inspect HTML responses inline for embedded <script language="VBScript">.
      • Endpoint hardening: Enable the Defender ASR rules "Block Office applications from creating child processes" and "Block execution of potentially obfuscated scripts". Enforce Exploit Protection (CFG, DEP, ASLR) on iexplore.exe. Office documents can also load the MSHTML/scripting engine.
      • Restrict Edge IE mode: Limit the Enterprise Mode Site List to the specific internal URLs that need it. Never allow external domains in IE mode.
      • Least privilege: Remove local admin rights from standard users. The exploit runs as the logged-on user, so restricted rights limit the impact until the attacker escalates.

    3. Runbook step 3

      Detection rules

      • Process ancestry (Sysmon EID 1 / Security 4688): iexplore.exe spawning cmd.exe, powershell.exe, mshta.exe, rundll32.exe, regsvr32.exe or wscript.exe. KQL: DeviceProcessEvents | where InitiatingProcessFileName =~ "iexplore.exe" and FileName in~ ("cmd.exe","powershell.exe","mshta.exe","rundll32.exe","regsvr32.exe")
      • Image loads (Sysmon EID 7): vbscript.dll loading into iexplore.exe or Office processes even though policy should block VBScript. This points to misconfiguration or a bypass.
      • File creation (Sysmon EID 11): iexplore.exe writing .exe, .dll or .ps1 files to %TEMP%, %APPDATA% or INetCache, followed shortly by their execution.
      • Proxy/Zeek http.log: An IE11 user agent hitting rare external domains, followed within seconds by a binary download (Content-Type: application/octet-stream). This is the typical landing → exploit → payload exploit-kit chain.
      • Crash telemetry (Application Event ID 1000): Clusters of iexplore.exe crashes with faulting module vbscript.dll or jscript9.dll can indicate failed exploitation attempts.

    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

    A remote code execution vulnerability exists in the way that the scripting engine handles objects in memory in Internet Explorer, aka 'Scripting Engine Memory Corruption Vulnerability'. This CVE ID is unique from CVE-2019-0739, CVE-2019-0753, CVE-2019-0862.

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

    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
    MicrosoftInternet Explorer 10
    • Windows Server 2012
    • —
    MicrosoftInternet Explorer 11
    • Windows 7 for x64-based Systems Service Pack 1
    • Windows RT 8.1
    • Windows Server 2008 R2 for x64-based Systems Service Pack 1
    • Windows Server 2012 R2
    • Windows 10 Version 1809 for x64-based Systems
    • Windows Server 2016
    • Windows 10 Version 1703 for x64-based Systems
    • Windows 10 Version 1607 for 32-bit Systems
    • Windows 10 Version 1703 for 32-bit Systems
    • Windows 7 for 32-bit Systems Service Pack 1
    • Windows 8.1 for x64-based systems
    • Windows 10 Version 1809 for ARM64-based Systems
    • Windows 10 Version 1709 for 32-bit Systems
    • Windows 10 Version 1803 for x64-based Systems
    • Windows 10 for 32-bit Systems
    • Windows 10 Version 1709 for ARM64-based Systems
    • Windows 10 Version 1709 for x64-based Systems
    • Windows Server 2019
    • Windows 10 Version 1809 for 32-bit Systems
    • Windows 8.1 for 32-bit systems
    • Windows 10 Version 1803 for ARM64-based Systems
    • Windows 10 for x64-based Systems
    • Windows 10 Version 1803 for 32-bit Systems
    • Windows 10 Version 1607 for x64-based Systems
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    microsoftinternet_explorer
    • 10
    • 11
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    Vendors and products

    Weakness classes (CWE)

    • CWE-843Access of Resource Using Incompatible Type ('Type Confusion')

      Base

      The product allocates or initializes a resource such as a pointer, object, or variable using one type, but it later accesses that resource using a type that is incompatible with the original type.

      Entry at MITRE CWE-843

    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
    Packet StormMicrosoft Internet Explorer Windows 10 1809 17763.316 Memory Corruption (opens in a new tab)packetstormsecurity.comPoC (publicly reported)reported, not verified—

    References & sources

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