CriticalCVE-2025-24991

    Windows NTFS Information Disclosure Vulnerability (CVE-2025-24991)

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

    What is affected, what to do

    Out-of-bounds read in Windows NTFS allows an authorized attacker to disclose information locally.

    The vulnerability is being actively exploited; treat it as a priority. Update Microsoft Windows 10 Version 1507 to version 10.0.10240.20947, Microsoft Windows 10 Version 1607 to version 10.0.14393.7876, Microsoft Windows 10 Version 1809 to version 10.0.17763.7009. Immediate actions, mitigation and detection rules are in the runbook below.

    Affected
    • Microsoft Windows 10 Version 1507 lt 10.0.10240.0..10.0.10240.20947
    • Microsoft Windows 10 Version 1607 lt 10.0.14393.0..10.0.14393.7876
    • Microsoft Windows 10 Version 1809 lt 10.0.17763.0..10.0.17763.7009
    • Microsoft Windows 10 Version 21H2 lt 10.0.19044.0..10.0.19044.5608
    • Microsoft Windows 10 Version 22H2 lt 10.0.19045.0..10.0.19045.5608
    • Microsoft Windows 11 version 22H2 lt 10.0.22621.0..10.0.22621.5039
    • Microsoft Windows 11 version 22H3 lt 10.0.22631.0..10.0.22631.5039
    • Microsoft Windows 11 Version 23H2 lt 10.0.22631.0..10.0.22631.5039
    • Microsoft Windows 11 Version 24H2 lt 10.0.26100.0..10.0.26100.3476
    • Microsoft Windows Server 2008 R2 Service Pack 1 lt 6.1.7601.0..6.1.7601.27618
    • Microsoft Windows Server 2008 R2 Service Pack 1 (Server Core installation) lt 6.1.7601.0..6.1.7601.27618
    • Microsoft Windows Server 2008 Service Pack 2 lt 6.0.6003.0..6.0.6003.23168
    • Microsoft Windows Server 2008 Service Pack 2 (Server Core installation) lt 6.0.6003.0..6.0.6003.23168
    • Microsoft Windows Server 2012 lt 6.2.9200.0..6.2.9200.25368
    • Microsoft Windows Server 2012 (Server Core installation) lt 6.2.9200.0..6.2.9200.25368
    • Microsoft Windows Server 2012 R2 lt 6.3.9600.0..6.3.9600.22470
    • Microsoft Windows Server 2012 R2 (Server Core installation) lt 6.3.9600.0..6.3.9600.22470
    • Microsoft Windows Server 2016 lt 10.0.14393.0..10.0.14393.7876
    • Microsoft Windows Server 2016 (Server Core installation) lt 10.0.14393.0..10.0.14393.7876
    • Microsoft Windows Server 2019 lt 10.0.17763.0..10.0.17763.7009
    • Microsoft Windows Server 2019 (Server Core installation) lt 10.0.17763.0..10.0.17763.7009
    • Microsoft Windows Server 2022 lt 10.0.20348.0..10.0.20348.3328
    • Microsoft Windows Server 2022, 23H2 Edition (Server Core installation) lt 10.0.25398.0..10.0.25398.1486
    • Microsoft Windows Server 2025 lt 10.0.26100.0..10.0.26100.3476
    • Microsoft Windows Server 2025 (Server Core installation) lt 10.0.26100.0..10.0.26100.3476
    Fixed in
    • Microsoft Windows 10 Version 1507 10.0.10240.20947
    • Microsoft Windows 10 Version 1607 10.0.14393.7876
    • Microsoft Windows 10 Version 1809 10.0.17763.7009
    • Microsoft Windows 10 Version 21H2 10.0.19044.5608
    • Microsoft Windows 10 Version 22H2 10.0.19045.5608
    • Microsoft Windows 11 version 22H2 10.0.22621.5039
    • Microsoft Windows 11 version 22H3 10.0.22631.5039
    • Microsoft Windows 11 Version 23H2 10.0.22631.5039
    • Microsoft Windows 11 Version 24H2 10.0.26100.3476
    • Microsoft Windows Server 2008 R2 Service Pack 1 6.1.7601.27618
    • Microsoft Windows Server 2008 R2 Service Pack 1 (Server Core installation) 6.1.7601.27618
    • Microsoft Windows Server 2008 Service Pack 2 6.0.6003.23168
    • Microsoft Windows Server 2008 Service Pack 2 (Server Core installation) 6.0.6003.23168
    • Microsoft Windows Server 2012 6.2.9200.25368
    • Microsoft Windows Server 2012 (Server Core installation) 6.2.9200.25368
    • Microsoft Windows Server 2012 R2 6.3.9600.22470
    • Microsoft Windows Server 2012 R2 (Server Core installation) 6.3.9600.22470
    • Microsoft Windows Server 2016 10.0.14393.7876
    • Microsoft Windows Server 2016 (Server Core installation) 10.0.14393.7876
    • Microsoft Windows Server 2019 10.0.17763.7009
    • Microsoft Windows Server 2019 (Server Core installation) 10.0.17763.7009
    • Microsoft Windows Server 2022 10.0.20348.3328
    • Microsoft Windows Server 2022, 23H2 Edition (Server Core installation) 10.0.25398.1486
    • Microsoft Windows Server 2025 10.0.26100.3476
    • Microsoft Windows Server 2025 (Server Core installation) 10.0.26100.3476

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

    Metrics

    5.5

    Priority

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

    Source: NVD, CVSS v3

    5.5

    CVSS v3

    Severity Medium on the scale from 0 to 10.

    Source: pwn.watch, CVE.org, Msrc Update Guide

    2.0 %

    EPSS score

    Moderate — model estimates 1-10% exploitation likelihood.

    Source: FIRST EPSS, percentile 80.9

    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
    187.97 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
    5.5 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
    5.5
    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
    2.0 %
    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
    80.9
    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 14 March 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-125

    Response and mitigation

    Why act now?

    Prioritisation rationale

    On its own, this flaw is local-only, needs user interaction and leaks memory contents rather than granting code execution. CISA added it to KEV because it was exploited as a zero-day alongside other NTFS bugs. Attackers typically deliver crafted VHD files via phishing to read heap memory and make follow-on exploits more reliable. Exploitation likelihood is elevated compared with the CVE population at large, and CISA does not flag known ransomware use. For organisations with large office-worker fleets and heavy email exposure, rate it high and patch within days on an expedited cycle. Hosts with no interactive user, such as servers without mail or browser use, can reasonably be treated as medium priority.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Deploy the Microsoft March 2025 (Patch Tuesday) security update and verify the build level on every client: Windows 10 1507 ≥ 10.0.10240.20947, 1607 ≥ 10.0.14393.7876, 1809 ≥ 10.0.17763.7009, 21H2/22H2 ≥ 10.0.19044.5608 and 10.0.19045.5608 respectively, Windows 11 22H2 ≥ 10.0.22621.5039, 23H2 ≥ 10.0.22631.5039. Look up the exact KB number per build in the Microsoft (MSRC) advisory.
      • Windows Server builds that share these code bases (e.g. builds 14393 and 17763) are not listed in the supplied context. Confirm Server edition coverage in the MSRC advisory and do not quietly exclude servers from the patch run.
      • Run a compliance query in Intune, SCCM or WSUS and ticket every endpoint below the listed builds with a 24-72 h due date. Prioritise devices with mail and browser use: user workstations, jump hosts and VDI.
      • Microsoft states that exploitation requires tricking a user into mounting a crafted virtual hard disk (VHD/VHDX). Quarantine .vhd, .vhdx and .iso attachments at the mail gateway now, and block those downloads at the web proxy.
      • Patch this together with the other NTFS and FAT flaws fixed the same day, notably CVE-2025-24993 (also on KEV). This information disclosure bug is a natural building block in an exploit chain.

    2. Runbook step 2

      Mitigation layers

      • Configuration/endpoint: Disable double-click mounting in Explorer. Push an empty REG_SZ value ProgrammaticAccessOnly via GPO under HKCR\Windows.VhdFile\shell\mount and HKCR\Windows.IsoFile\shell\mount. Create an exemption group for legitimate users such as Hyper-V administrators.
      • Mail/web filtering: Block or sandbox container formats (.vhd, .vhdx, .iso, .img) at the secure email gateway and the proxy, including inside ZIP and 7z archives. Use magic-byte detection (VHDX signature vhdxfile, VHD footer conectix) rather than relying on file extensions.
      • IAM/least privilege: Remove local admin rights or manage them through LAPS. Protect in-memory secrets with Credential Guard and LSA protection (RunAsPPL) so that leaked memory is less valuable to an attacker.
      • Application control: Use WDAC or AppLocker rules to block execution from removable or virtual-disk drive letters. This breaks follow-on activity after a malicious mount.
      • User awareness: Send staff a short advisory not to open unexpected disk-image attachments or downloads, and to report suspicious ones to the SOC.

    3. Runbook step 3

      Detection rules

      • VHD mount events: Collect Microsoft-Windows-VHDMP/Operational (the surface events logged when a disk is mounted). Alert on mounts by non-admin users, or on image paths under \Downloads\, \AppData\Local\Temp\ or \Content.Outlook\.
      • Sysmon EID 11/15: Flag creation of *.vhd/*.vhdx files carrying a Zone.Identifier with ZoneId=3 (downloaded from the internet). Example KQL: DeviceFileEvents | where FileName endswith ".vhd" or FileName endswith ".vhdx" | where FileOriginUrl != "" or FolderPath has_any ("Downloads","Temp","Content.Outlook")
      • PowerShell ScriptBlock (EID 4104): Hunt for Mount-DiskImage, Mount-VHD, or diskpart with attach vdisk on hosts that are not known admin systems. Sigma shape: ScriptBlockText|contains: ['Mount-DiskImage','Mount-VHD','attach vdisk']
      • EDR process ancestry: Watch for the chain outlook.exe/browser → explorer.exe (mount) → process launch from a newly assigned drive letter. Also watch for unusual raw reads of \Device\HarddiskVolume* immediately after a mount.
      • Mail gateway logs: Correlate delivered or blocked container attachments with VHDMP mount events on the recipient's host. Triage any matches first.

    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

    Out-of-bounds read in Windows NTFS allows an authorized attacker to disclose information locally.

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

    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 – < 10.0.10240.20947
    • 10.0.10240.20947
    MicrosoftWindows 10 Version 1607
    • 10.0.14393.0 – < 10.0.14393.7876
    • 10.0.14393.7876
    MicrosoftWindows 10 Version 1809
    • 10.0.17763.0 – < 10.0.17763.7009
    • 10.0.17763.7009
    MicrosoftWindows 10 Version 21H2
    • 10.0.19044.0 – < 10.0.19044.5608
    • 10.0.19044.5608
    MicrosoftWindows 10 Version 22H2
    • 10.0.19045.0 – < 10.0.19045.5608
    • 10.0.19045.5608
    MicrosoftWindows 11 version 22H2
    • 10.0.22621.0 – < 10.0.22621.5039
    • 10.0.22621.5039
    MicrosoftWindows 11 version 22H3
    • 10.0.22631.0 – < 10.0.22631.5039
    • 10.0.22631.5039
    MicrosoftWindows 11 Version 23H2
    • 10.0.22631.0 – < 10.0.22631.5039
    • 10.0.22631.5039
    MicrosoftWindows 11 Version 24H2
    • 10.0.26100.0 – < 10.0.26100.3476
    • 10.0.26100.3476
    MicrosoftWindows Server 2008 R2 Service Pack 1
    • 6.1.7601.0 – < 6.1.7601.27618
    • 6.1.7601.27618
    MicrosoftWindows Server 2008 R2 Service Pack 1 (Server Core installation)
    • 6.1.7601.0 – < 6.1.7601.27618
    • 6.1.7601.27618
    MicrosoftWindows Server 2008 Service Pack 2
    • 6.0.6003.0 – < 6.0.6003.23168
    • 6.0.6003.23168
    MicrosoftWindows Server 2008 Service Pack 2 (Server Core installation)
    • 6.0.6003.0 – < 6.0.6003.23168
    • 6.0.6003.23168
    MicrosoftWindows Server 2012
    • 6.2.9200.0 – < 6.2.9200.25368
    • 6.2.9200.25368
    MicrosoftWindows Server 2012 (Server Core installation)
    • 6.2.9200.0 – < 6.2.9200.25368
    • 6.2.9200.25368
    MicrosoftWindows Server 2012 R2
    • 6.3.9600.0 – < 6.3.9600.22470
    • 6.3.9600.22470
    MicrosoftWindows Server 2012 R2 (Server Core installation)
    • 6.3.9600.0 – < 6.3.9600.22470
    • 6.3.9600.22470
    MicrosoftWindows Server 2016
    • 10.0.14393.0 – < 10.0.14393.7876
    • 10.0.14393.7876
    MicrosoftWindows Server 2016 (Server Core installation)
    • 10.0.14393.0 – < 10.0.14393.7876
    • 10.0.14393.7876
    MicrosoftWindows Server 2019
    • 10.0.17763.0 – < 10.0.17763.7009
    • 10.0.17763.7009
    MicrosoftWindows Server 2019 (Server Core installation)
    • 10.0.17763.0 – < 10.0.17763.7009
    • 10.0.17763.7009
    MicrosoftWindows Server 2022
    • 10.0.20348.0 – < 10.0.20348.3328
    • 10.0.20348.3328
    MicrosoftWindows Server 2022, 23H2 Edition (Server Core installation)
    • 10.0.25398.0 – < 10.0.25398.1486
    • 10.0.25398.1486
    MicrosoftWindows Server 2025
    • 10.0.26100.0 – < 10.0.26100.3476
    • 10.0.26100.3476
    MicrosoftWindows Server 2025 (Server Core installation)
    • 10.0.26100.0 – < 10.0.26100.3476
    • 10.0.26100.3476

    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-125Out-of-bounds Read

      Base

      The product reads data past the end, or before the beginning, of the intended buffer.

      Entry at MITRE CWE-125

    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

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    Badge preview for CVE-2025-24991
    <a href="https://intel.neosec.eu/en/cve/CVE-2025-24991"><img src="https://intel.neosec.eu/badge/cve/CVE-2025-24991.svg?lang=en" alt="CVE-2025-24991 – NEOSEC Intel" height="20"></a>