CriticalCVE-2025-30397

    Scripting Engine Memory Corruption Vulnerability (CVE-2025-30397)

    Published In CISA KEV since Sources: CVE.org, pwn.watch, Msrc Update Guide

    What is affected, what to do

    Access of resource using incompatible type ('type confusion') in Microsoft Scripting Engine allows an unauthorized attacker to execute code over a network.

    The vulnerability is being actively exploited; treat it as a priority. Update Microsoft Windows Server 2016 (Server Core installation) to version 10.0.14393.8066, Microsoft Windows 10 Version 1507 to version 10.0.10240.21014, Microsoft Windows 10 Version 1607 to version 10.0.14393.8066. Immediate actions, mitigation and detection rules are in the runbook below.

    Affected
    • Microsoft Windows Server 2016 (Server Core installation) lt 10.0.14393.0..10.0.14393.8066
    • Microsoft Windows 10 Version 1507 lt 10.0.10240.0..10.0.10240.21014
    • Microsoft Windows 10 Version 1607 lt 10.0.14393.0..10.0.14393.8066
    • Microsoft Windows 10 Version 1809 lt 10.0.17763.0..10.0.17763.7314
    • Microsoft Windows 10 Version 21H2 lt 10.0.19044.0..10.0.19044.5854
    • Microsoft Windows 10 Version 22H2 lt 10.0.19045.0..10.0.19045.5854
    • Microsoft Windows 11 version 22H2 lt 10.0.22621.0..10.0.22621.5335
    • Microsoft Windows 11 version 22H3 lt 10.0.22631.0..10.0.22631.5335
    • Microsoft Windows 11 Version 23H2 lt 10.0.22631.0..10.0.22631.5335
    • Microsoft Windows 11 Version 24H2 lt 10.0.26100.0..10.0.26100.4061
    • Microsoft Windows Server 2008 R2 Service Pack 1 lt 6.1.7601.0..6.1.7601.27729
    • Microsoft Windows Server 2008 R2 Service Pack 1 (Server Core installation) lt 6.1.7601.0..6.1.7601.27729
    • Microsoft Windows Server 2008 Service Pack 2 lt 6.0.6003.0..6.0.6003.23279
    • Microsoft Windows Server 2008 Service Pack 2 (Server Core installation) lt 6.0.6003.0..6.0.6003.23279
    • Microsoft Windows Server 2012 lt 6.2.9200.0..6.2.9200.25475
    • Microsoft Windows Server 2012 (Server Core installation) lt 6.2.9200.0..6.2.9200.25475
    • Microsoft Windows Server 2012 R2 lt 6.3.9600.0..6.3.9600.22577
    • Microsoft Windows Server 2012 R2 (Server Core installation) lt 6.3.9600.0..6.3.9600.22577
    • Microsoft Windows Server 2016 lt 10.0.14393.0..10.0.14393.8066
    • Microsoft Windows Server 2019 lt 10.0.17763.0..10.0.17763.7314
    • Microsoft Windows Server 2019 (Server Core installation) lt 10.0.17763.0..10.0.17763.7314
    • Microsoft Windows Server 2022 lt 10.0.20348.0..10.0.20348.3692
    • Microsoft Windows Server 2022, 23H2 Edition (Server Core installation) lt 10.0.25398.0..10.0.25398.1611
    • Microsoft Windows Server 2025 lt 10.0.26100.0..10.0.26100.4061
    • Microsoft Windows Server 2025 (Server Core installation) lt 10.0.26100.0..10.0.26100.4061
    Fixed in
    • Microsoft Windows Server 2016 (Server Core installation) 10.0.14393.8066
    • Microsoft Windows 10 Version 1507 10.0.10240.21014
    • Microsoft Windows 10 Version 1607 10.0.14393.8066
    • Microsoft Windows 10 Version 1809 10.0.17763.7314
    • Microsoft Windows 10 Version 21H2 10.0.19044.5854
    • Microsoft Windows 10 Version 22H2 10.0.19045.5854
    • Microsoft Windows 11 version 22H2 10.0.22621.5335
    • Microsoft Windows 11 version 22H3 10.0.22631.5335
    • Microsoft Windows 11 Version 23H2 10.0.22631.5335
    • Microsoft Windows 11 Version 24H2 10.0.26100.4061
    • Microsoft Windows Server 2008 R2 Service Pack 1 6.1.7601.27729
    • Microsoft Windows Server 2008 R2 Service Pack 1 (Server Core installation) 6.1.7601.27729
    • Microsoft Windows Server 2008 Service Pack 2 6.0.6003.23279
    • Microsoft Windows Server 2008 Service Pack 2 (Server Core installation) 6.0.6003.23279
    • Microsoft Windows Server 2012 6.2.9200.25475
    • Microsoft Windows Server 2012 (Server Core installation) 6.2.9200.25475
    • Microsoft Windows Server 2012 R2 6.3.9600.22577
    • Microsoft Windows Server 2012 R2 (Server Core installation) 6.3.9600.22577
    • Microsoft Windows Server 2016 10.0.14393.8066
    • Microsoft Windows Server 2019 10.0.17763.7314
    • Microsoft Windows Server 2019 (Server Core installation) 10.0.17763.7314
    • Microsoft Windows Server 2022 10.0.20348.3692
    • Microsoft Windows Server 2022, 23H2 Edition (Server Core installation) 10.0.25398.1611
    • Microsoft Windows Server 2025 10.0.26100.4061
    • Microsoft Windows Server 2025 (Server Core installation) 10.0.26100.4061

    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, pwn.watch, Msrc Update Guide

    27.3 %

    EPSS score

    Elevated — model estimates 10-50% exploitation likelihood.

    Source: FIRST EPSS, percentile 98.1

    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
    223.41 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
    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
    27.3 %
    Elevated — model estimates 10-50% 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
    98.1
    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
    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

    Microsoft fixed this flaw as a zero-day that was already being exploited when the patch shipped. It is reachable over the network without authentication, but it needs user interaction (opening a crafted URL) and has higher attack complexity. According to the vendor, it typically requires content to be rendered in an IE-mode context. Exploitation likelihood is very high, and success yields code execution as the logged-on user. That makes it well suited to targeted phishing against organisations that still run legacy web apps, commonly public administration, critical-infrastructure operators and manufacturing. CISA does not flag known ransomware use. Organisations with IE mode enabled should treat this as critical and patch within 72 h. Where IE mode is disabled fleet-wide, the standard expedited patch window is sufficient.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Deploy the May 2025 security update (Patch Tuesday, 13 May 2025) and verify minimum builds: Windows 11 22H2 ≥ 10.0.22621.5335, Windows 11 23H2/"22H3" ≥ 10.0.22631.5335, Windows 10 22H2 ≥ 10.0.19045.5854, 21H2 ≥ 10.0.19044.5854, 1809 ≥ 10.0.17763.7314, 1607 ≥ 10.0.14393.8066, 1507 ≥ 10.0.10240.21014. Look up the KB number for each build in the MSRC advisory. Windows Server editions are not listed in this context, so check the advisory for their exposure as well.
      • Identify unpatched hosts: in Defender for Endpoint, run DeviceTvmSoftwareVulnerabilities | where CveId == "CVE-2025-30397" | summarize by DeviceName, OSVersion. Alternatively, compare OS builds from Intune, SCCM or WSUS reports against the minimums above.
      • Sequence the rollout: patch endpoints with Edge Internet Explorer mode enabled first (legacy intranet, line-of-business web apps). Admin workstations and privileged users come next, then the remaining fleet.
      • Restrict IE mode temporarily wherever patching cannot finish within 24 h (see mitigation layers). Notify business units that depend on it beforehand.
      • Warn users: send a short advisory about unexpected links in email, Teams and messengers. Exploitation requires the victim to open a crafted URL.

    2. Runbook step 2

      Mitigation layers

      • Configuration (Edge policy): set InternetExplorerIntegrationLevel = 0 via GPO or Intune. If IE mode is business-critical, at minimum set InternetExplorerIntegrationReloadInIEModeAllowed = 0 and allow IE mode only through an Enterprise Site List of approved intranet URLs.
      • Endpoint hardening (ASR): enable these Attack Surface Reduction rules in block mode: "Block JavaScript or VBScript from launching downloaded executable content" (d3e037e1-3eb8-44c8-a917-57927947596d) and "Block executable files from running unless they meet a prevalence, age, or trusted list criterion". Back them with WDAC or AppLocker rules that deny execution from %TEMP% and %LOCALAPPDATA%.
      • Legacy scripting: via GPO, set "Active Scripting" to Disable in the IE Internet and Restricted Sites zones. This prevents jscript9.dll from executing external content in the IE context.
      • Network / proxy: block or TLS-inspect the "Newly Registered Domains" and "Uncategorized" categories for client traffic. Restrict iexplore.exe egress to internal destinations only (intranet allowlist).
      • IAM / least privilege: remove local admin rights from standard users and enforce separate PAWs for administration. Code runs in the logged-on user's context, so low privileges limit the blast radius.

    3. Runbook step 3

      Detection rules

      • Process ancestry (Sysmon EID 1 / EDR): flag suspicious children of iexplore.exe, which runs under msedge.exe in IE mode. KQL: DeviceProcessEvents | where InitiatingProcessFileName =~ "iexplore.exe" and FileName in~ ("cmd.exe","powershell.exe","pwsh.exe","rundll32.exe","regsvr32.exe","mshta.exe","wscript.exe","cscript.exe").
      • Module loads (Sysmon EID 7): track loads of jscript9.dll into iexplore.exe and correlate them with page loads from external domains. On hosts with no approved IE-mode sites, any such load is anomalous.
      • Crash signals (Application log, EID 1000/1001): application faults with Faulting module name: jscript9.dll may indicate failed exploit attempts. SPL: index=wineventlog EventCode=1000 Faulting_Module_Name="jscript9.dll".
      • File system and persistence (Sysmon EID 11/13): look for executables or DLLs written by iexplore.exe into user profile paths. Also watch for Run-key or scheduled-task creation shortly after an IE-mode page load, and review ASR events EID 1121/1122 (Microsoft-Windows-Windows Defender/Operational).
      • Network telemetry (proxy/Zeek): flag HTTP(S) sessions from iexplore.exe, or with the IE-mode user agent (Trident/7.0), to rare external domains. Sigma skeleton: logsource: proxy with c-useragent|contains: 'Trident/7.0', filtering cs-host outside the intranet allowlist.

    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

    Access of resource using incompatible type ('type confusion') in Microsoft Scripting Engine allows an unauthorized attacker to execute code over a network.

    Source: cvelistv5, NVD (NIST), CISA KEV Catalog, CVE.org (MITRE), pwn.watch, Microsoft Security Update Guide

    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 Version 1507
    • 10.0.10240.0 – < 10.0.10240.21014
    • 10.0.10240.21014
    MicrosoftWindows 10 Version 1607
    • 10.0.14393.0 – < 10.0.14393.8066
    • 10.0.14393.8066
    MicrosoftWindows 10 Version 1809
    • 10.0.17763.0 – < 10.0.17763.7314
    • 10.0.17763.7314
    MicrosoftWindows 10 Version 21H2
    • 10.0.19044.0 – < 10.0.19044.5854
    • 10.0.19044.5854
    MicrosoftWindows 10 Version 22H2
    • 10.0.19045.0 – < 10.0.19045.5854
    • 10.0.19045.5854
    MicrosoftWindows 11 version 22H2
    • 10.0.22621.0 – < 10.0.22621.5335
    • 10.0.22621.5335
    MicrosoftWindows 11 version 22H3
    • 10.0.22631.0 – < 10.0.22631.5335
    • 10.0.22631.5335
    MicrosoftWindows 11 Version 23H2
    • 10.0.22631.0 – < 10.0.22631.5335
    • 10.0.22631.5335
    MicrosoftWindows 11 Version 24H2
    • 10.0.26100.0 – < 10.0.26100.4061
    • 10.0.26100.4061
    MicrosoftWindows Server 2008 R2 Service Pack 1
    • 6.1.7601.0 – < 6.1.7601.27729
    • 6.1.7601.27729
    MicrosoftWindows Server 2008 R2 Service Pack 1 (Server Core installation)
    • 6.1.7601.0 – < 6.1.7601.27729
    • 6.1.7601.27729
    MicrosoftWindows Server 2008 Service Pack 2
    • 6.0.6003.0 – < 6.0.6003.23279
    • 6.0.6003.23279
    MicrosoftWindows Server 2008 Service Pack 2 (Server Core installation)
    • 6.0.6003.0 – < 6.0.6003.23279
    • 6.0.6003.23279
    MicrosoftWindows Server 2012
    • 6.2.9200.0 – < 6.2.9200.25475
    • 6.2.9200.25475
    MicrosoftWindows Server 2012 (Server Core installation)
    • 6.2.9200.0 – < 6.2.9200.25475
    • 6.2.9200.25475
    MicrosoftWindows Server 2012 R2
    • 6.3.9600.0 – < 6.3.9600.22577
    • 6.3.9600.22577
    MicrosoftWindows Server 2012 R2 (Server Core installation)
    • 6.3.9600.0 – < 6.3.9600.22577
    • 6.3.9600.22577
    MicrosoftWindows Server 2016
    • 10.0.14393.0 – < 10.0.14393.8066
    • 10.0.14393.8066
    MicrosoftWindows Server 2016 (Server Core installation)
    • 10.0.14393.0 – < 10.0.14393.8066
    • 10.0.14393.8066
    MicrosoftWindows Server 2019
    • 10.0.17763.0 – < 10.0.17763.7314
    • 10.0.17763.7314
    MicrosoftWindows Server 2019 (Server Core installation)
    • 10.0.17763.0 – < 10.0.17763.7314
    • 10.0.17763.7314
    MicrosoftWindows Server 2022
    • 10.0.20348.0 – < 10.0.20348.3692
    • 10.0.20348.3692
    MicrosoftWindows Server 2022, 23H2 Edition (Server Core installation)
    • 10.0.25398.0 – < 10.0.25398.1611
    • 10.0.25398.1611
    MicrosoftWindows Server 2025
    • 10.0.26100.0 – < 10.0.26100.4061
    • 10.0.26100.4061
    MicrosoftWindows Server 2025 (Server Core installation)
    • 10.0.26100.0 – < 10.0.26100.4061
    • 10.0.26100.4061

    Vendors and products

    Affected operating systems

    Affected operating systems
    Windowsmicrosoftwindows_10_1507—
    Windowsmicrosoftwindows_10_1607—
    Windowsmicrosoftwindows_10_1809—
    Windowsmicrosoftwindows_10_21h2—
    Windowsmicrosoftwindows_10_22h2—
    Windowsmicrosoftwindows_11_22h2—
    Windowsmicrosoftwindows_11_23h2—
    Windowsmicrosoftwindows_11_24h2—
    Windowsmicrosoftwindows_server_2008r2
    Windowsmicrosoftwindows_server_2008—
    Windowsmicrosoftwindows_server_2012r2
    Windowsmicrosoftwindows_server_2012—
    Windowsmicrosoftwindows_server_2016—
    Windowsmicrosoftwindows_server_2019—
    Windowsmicrosoftwindows_server_2022—
    Windowsmicrosoftwindows_server_2022_23h2—
    Windowsmicrosoftwindows_server_2025—

    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

    References & sources

    Embed badge

    Show the severity and KEV status of this vulnerability on your site – with a link back here. The image is updated hourly.

    Badge preview for CVE-2025-30397
    <a href="https://intel.neosec.eu/en/cve/CVE-2025-30397"><img src="https://intel.neosec.eu/badge/cve/CVE-2025-30397.svg?lang=en" alt="CVE-2025-30397 – NEOSEC Intel" height="20"></a>