CriticalCVE-2025-24983

    Windows Win32 Kernel Subsystem Elevation of Privilege Vulnerability (CVE-2025-24983)

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

    What is affected, what to do

    Use after free in Windows Win32 Kernel Subsystem allows an authorized attacker to elevate privileges 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 Server 2008 R2 Service Pack 1 to version 6.1.7601.27618. 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 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
    Fixed in
    • Microsoft Windows 10 Version 1507 10.0.10240.20947
    • Microsoft Windows 10 Version 1607 10.0.14393.7876
    • 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

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

    Metrics

    7.0

    Priority

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

    Source: NVD, CVSS v3

    7.0

    CVSS v3

    Severity High on the scale from 0 to 10.

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

    1.9 %

    EPSS score

    Moderate — model estimates 1-10% exploitation likelihood.

    Source: FIRST EPSS, percentile 79.2

    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
    193.36 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
    7.0 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
    7.0
    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
    1.9 %
    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
    79.2
    High — this CVE ranks above the median of all CVEs scored today (rank ≥ 36%).
    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-416

    Response and mitigation

    Why act now?

    Prioritisation rationale

    This is a local privilege-escalation primitive: attackers chain it after gaining code execution as a standard user (phishing, loaders, hijacked remote sessions) to obtain SYSTEM, disable security tooling and harvest credentials. High attack complexity and the need for local access make it unsuitable for mass exploitation, overall exploitation likelihood is moderate, and CISA reports no known ransomware use. Only legacy Windows versions are affected — but in KRITIS and OT-adjacent estates these often sit on hard-to-patch systems. Treat it as high priority for multi-user and legacy hosts lacking ESU, and handle single-user endpoints with working EDR and application control within your regular patch SLA.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Deploy the security update: Roll out the March 2025 Patch Tuesday cumulative update to every affected system. Minimum fixed builds: Windows 10 1507 → 10.0.10240.20947, Windows 10 1607 / Server 2016 base → 10.0.14393.7876, Server 2008 R2 SP1 (incl. Server Core) → 6.1.7601.27618, Server 2008 SP2 (incl. Server Core) → 6.0.6003.23168, Server 2012 → 6.2.9200.25368, Server 2012 R2 → 6.3.9600.22470. Look up the KB numbers in Microsoft's advisory for CVE-2025-24983.
      • Check ESU coverage: Server 2008/2008 R2/2012/2012 R2 and Windows 10 1507 generally receive fixes only via Extended Security Updates. Treat any host without an active ESU licence as unpatched and flag it as high risk.
      • Verify patch level: Pull build numbers from inventory, e.g. Get-ItemProperty 'HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion' | Select CurrentBuild,UBR, and compare against the fixed builds above.
      • Patch multi-user hosts first: RDS/terminal servers, Citrix VDAs, jump hosts and any system with many interactive users — these give an attacker holding a low-privileged account the best starting position.
      • Triage suspected compromises: On hosts with a known initial-access event (malware detection, phishing execution), look for SYSTEM processes spawned from user context; if found, isolate the host and rotate local and cached privileged credentials.

    2. Runbook step 2

      Mitigation layers

      • Application control (endpoint hardening): Enforce WDAC or AppLocker policies blocking execution from user-writable paths (%TEMP%, %APPDATA%, Downloads, C:\Users\Public) — a local exploit must first be dropped and launched as a binary or loader.
      • IAM / least privilege: Restrict interactive logon on servers to administrators ("Allow log on locally" / "Allow log on through Remote Desktop Services" via GPO); enforce an admin tiering model so a local privilege escalation does not hand over domain-admin credentials.
      • Credential protection: Enable Credential Guard and LSA protection (RunAsPPL) to blunt the usual next step after reaching SYSTEM — dumping LSASS.
      • Segmentation for legacy systems: Move unpatchable Server 2008/2012 hosts into a dedicated VLAN, allow RDP (TCP 3389) and SMB (TCP 445) only from defined admin jump hosts, and block outbound internet traffic.
      • EDR protections: Switch Exploit Protection / ASR rules (e.g. "Block process creations originating from PSExec and WMI commands", "Block executable files unless they meet a prevalence, age, or trusted list criterion") to block mode.

    3. Runbook step 3

      Detection rules

      • Integrity-level jump in process ancestry (Sysmon EID 1 / Security 4688): a process running as IntegrityLevel=System / NT AUTHORITY\SYSTEM whose parent runs at Medium integrity under a standard user and is not a legitimate service broker. KQL: DeviceProcessEvents | where ProcessIntegrityLevel == "System" and InitiatingProcessIntegrityLevel in ("Medium","Low") and InitiatingProcessFileName !in~ ("services.exe","svchost.exe","msiexec.exe")
      • Post-escalation activity: new services (System 7045, Security 4697) or scheduled tasks (Security 4698) shortly after a non-admin logon; lsass.exe access (Sysmon EID 10, GrantedAccess 0x1010/0x1FFFFF) from unusual processes.
      • Win32k instability: bugchecks or crash reports referencing win32k*.sys (System log Event 1001 "BugCheck", Application 1000/1001) — failed use-after-free attempts frequently blue-screen the host; investigate clusters on a single machine.
      • Unsigned binaries from user paths: Sysmon EID 1/EID 7 with Image under \Users\*\AppData\ or \Temp\ and no valid signature, followed by token manipulation or a SYSTEM child process (Sigma shape: selection_path + selection_unsigned, correlated with a SYSTEM child process within 5 min).

    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

    Use after free in Windows Win32 Kernel Subsystem allows an authorized attacker to elevate privileges locally.

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

    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 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

    Vendors and products

    Affected operating systems

    Affected operating systems
    Windowsmicrosoftwindows_10_1507—
    Windowsmicrosoftwindows_10_1607—
    Windowsmicrosoftwindows_server_2008r2
    Windowsmicrosoftwindows_server_2008—
    Windowsmicrosoftwindows_server_2012r2
    Windowsmicrosoftwindows_server_2012—
    Windowsmicrosoftwindows_server_2016—

    Weakness classes (CWE)

    • CWE-416Use After Free

      Variant

      The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

      Entry at MITRE CWE-416

    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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