CriticalCVE-2025-24990

    Windows Agere Modem Driver Elevation of Privilege Vulnerability (CVE-2025-24990)

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

    What is affected, what to do

    Microsoft is aware of vulnerabilities in the third party Agere Modem driver that ships natively with supported Windows operating systems. This is an announcement of the upcoming removal of ltmdm64.sys driver.

    The vulnerability is being actively exploited; treat it as a priority. Update Microsoft Windows 10 Version 1507 to version 10.0.10240.21161, Microsoft Windows 10 Version 1607 to version 10.0.14393.8519, Microsoft Windows 10 Version 1809 to version 10.0.17763.7919. Immediate actions, mitigation and detection rules are in the runbook below.

    Affected
    • Microsoft Windows 10 Version 1507 lt 10.0.10240.0..10.0.10240.21161
    • Microsoft Windows 10 Version 1607 lt 10.0.14393.0..10.0.14393.8519
    • Microsoft Windows 10 Version 1809 lt 10.0.17763.0..10.0.17763.7919
    • Microsoft Windows 10 Version 21H2 lt 10.0.19044.0..10.0.19044.6456
    • Microsoft Windows 10 Version 22H2 lt 10.0.19045.0..10.0.19045.6456
    • Microsoft Windows 11 version 22H2 lt 10.0.22621.0..10.0.22621.6060
    • Microsoft Windows 11 Version 23H2 lt 10.0.22631.0..10.0.22631.6060
    • Microsoft Windows 11 Version 24H2 lt 10.0.26100.0..10.0.26100.6899
    • Microsoft Windows 11 Version 25H2 lt 10.0.26200.0..10.0.26200.6899
    • Microsoft Windows Server 2008 R2 Service Pack 1 lt 6.1.7601.0..6.1.7601.27974
    • Microsoft Windows Server 2008 R2 Service Pack 1 (Server Core installation) lt 6.1.7601.0..6.1.7601.27974
    • Microsoft Windows Server 2008 Service Pack 2 lt 6.0.6003.0..6.0.6003.23571
    • Microsoft Windows Server 2008 Service Pack 2 (Server Core installation) lt 6.0.6003.0..6.0.6003.23571
    • Microsoft Windows Server 2012 lt 6.2.9200.0..6.2.9200.25722
    • Microsoft Windows Server 2012 (Server Core installation) lt 6.2.9200.0..6.2.9200.25722
    • Microsoft Windows Server 2012 R2 lt 6.3.9600.0..6.3.9600.22824
    • Microsoft Windows Server 2012 R2 (Server Core installation) lt 6.3.9600.0..6.3.9600.22824
    • Microsoft Windows Server 2016 lt 10.0.14393.0..10.0.14393.8519
    • Microsoft Windows Server 2016 (Server Core installation) lt 10.0.14393.0..10.0.14393.8519
    • Microsoft Windows Server 2019 lt 10.0.17763.0..10.0.17763.7919
    • Microsoft Windows Server 2019 (Server Core installation) lt 10.0.17763.0..10.0.17763.7919
    • Microsoft Windows Server 2022 lt 10.0.20348.0..10.0.20348.4294
    • Microsoft Windows Server 2022, 23H2 Edition (Server Core installation) lt 10.0.25398.0..10.0.25398.1913
    • Microsoft Windows Server 2025 lt 10.0.26100.0..10.0.26100.6899
    • Microsoft Windows Server 2025 (Server Core installation) lt 10.0.26100.0..10.0.26100.6899
    Fixed in
    • Microsoft Windows 10 Version 1507 10.0.10240.21161
    • Microsoft Windows 10 Version 1607 10.0.14393.8519
    • Microsoft Windows 10 Version 1809 10.0.17763.7919
    • Microsoft Windows 10 Version 21H2 10.0.19044.6456
    • Microsoft Windows 10 Version 22H2 10.0.19045.6456
    • Microsoft Windows 11 version 22H2 10.0.22621.6060
    • Microsoft Windows 11 Version 23H2 10.0.22631.6060
    • Microsoft Windows 11 Version 24H2 10.0.26100.6899
    • Microsoft Windows 11 Version 25H2 10.0.26200.6899
    • Microsoft Windows Server 2008 R2 Service Pack 1 6.1.7601.27974
    • Microsoft Windows Server 2008 R2 Service Pack 1 (Server Core installation) 6.1.7601.27974
    • Microsoft Windows Server 2008 Service Pack 2 6.0.6003.23571
    • Microsoft Windows Server 2008 Service Pack 2 (Server Core installation) 6.0.6003.23571
    • Microsoft Windows Server 2012 6.2.9200.25722
    • Microsoft Windows Server 2012 (Server Core installation) 6.2.9200.25722
    • Microsoft Windows Server 2012 R2 6.3.9600.22824
    • Microsoft Windows Server 2012 R2 (Server Core installation) 6.3.9600.22824
    • Microsoft Windows Server 2016 10.0.14393.8519
    • Microsoft Windows Server 2016 (Server Core installation) 10.0.14393.8519
    • Microsoft Windows Server 2019 10.0.17763.7919
    • Microsoft Windows Server 2019 (Server Core installation) 10.0.17763.7919
    • Microsoft Windows Server 2022 10.0.20348.4294
    • Microsoft Windows Server 2022, 23H2 Edition (Server Core installation) 10.0.25398.1913
    • Microsoft Windows Server 2025 10.0.26100.6899
    • Microsoft Windows Server 2025 (Server Core installation) 10.0.26100.6899

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

    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, pwn.watch, Msrc Update Guide

    6.4 %

    EPSS score

    Moderate — model estimates 1-10% exploitation likelihood.

    Source: FIRST EPSS, percentile 93.7

    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
    220.60 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
    7.8 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
    6.4 %
    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
    93.7
    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 15 October 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-822

    Response and mitigation

    Why act now?

    Prioritisation rationale

    This is a local privilege escalation that requires only low privileges and no user interaction, yet gives full control of confidentiality, integrity and availability. Attackers chain it after phishing, stolen VPN access or web shells to reach SYSTEM, disable EDR and harvest credentials. The key amplifier is that the driver shipped inbox on essentially every Windows install, whether or not modem hardware was present, so the exposed surface is your entire client and session-host estate. Exploitation likelihood is markedly elevated compared to most CVEs, and CISA does not flag known ransomware use. Recommendation: patch shared and admin systems within days at high priority, and roll out to the rest of the fleet on an accelerated regular cycle. Keep any fax-dependent holdouts as documented exceptions protected by a WDAC block.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Fast-track the October 2025 Windows cumulative update. It removes ltmdm64.sys entirely. Minimum target builds per the advisory:

        • Win10 1507: 10.0.10240.21161
        • Win10 1607: 10.0.14393.8519
        • Win10 1809: 10.0.17763.7919
        • Win10 21H2/22H2: 10.0.19044.6456 / 10.0.19045.6456
        • Win11 22H2/23H2: 10.0.22621.6060 / 10.0.22631.6060
        • Win11 24H2: 10.0.26100.6899

        Look up the KB number in the Microsoft Security Update Guide.

      • Find every host that still lacks the update. Query Intune, SCCM or your EDR inventory for builds below target. Confirm on the host that the driver is gone: Get-CimInstance Win32_SystemDriver | Where-Object PathName -like '*ltmdm64*' or Test-Path C:\Windows\System32\drivers\ltmdm64.sys.

      • Patch multi-user systems first. This means RDS/Citrix hosts, VDI golden images, jump hosts and admin workstations, where many unprivileged accounts can run local code.

      • Inventory fax-modem dependencies. Agere/LSI soft-modem hardware stops working after the update. Engage the business owners now (healthcare, logistics and dispatch fax workflows are typical) and plan a move to FoIP or cloud fax. Do not pause patching to accommodate this.

      • If you suspect compromise: Isolate the host and rotate local admin credentials via LAPS. Treat any domain credentials cached on that host as compromised.

    2. Runbook step 2

      Mitigation layers

      • Application and driver control: Deploy a WDAC/App Control deny rule for ltmdm64.sys (file name plus hash or publisher rule) in enforced mode. This blocks the driver from loading on unpatched machines and prevents BYOVD reintroduction on patched ones. Enable HVCI/Memory Integrity and enforce the Microsoft Vulnerable Driver Blocklist.
      • Configuration change if patching lags: Block the driver through the device-installation restriction Group Policy. Where no modem hardware is needed, disable or prevent the driver service from starting. Pilot this on a test ring first.
      • Make initial access harder: The flaw can only be exploited locally, so the attacker first needs code execution as a standard user. These controls shrink that first stage:
        • ASR rules (Office child processes, executable content from email/webmail, obfuscated scripts)
        • AppLocker or WDAC for user-writable paths (%APPDATA%, %TEMP%, Downloads)
        • Macro blocking
      • IAM/least privilege: Restrict interactive logon on servers and shared hosts to the minimum needed. Enforce admin tiering so that local privilege escalation does not hand over Tier-0 credentials. Enable LSA protection (RunAsPPL) and Credential Guard.
      • Network segmentation: Move legacy fax-dependent machines that cannot be patched into a dedicated VLAN. Block SMB, RDP and WinRM from that VLAN to server and admin networks to contain lateral movement after a successful escalation.

    3. Runbook step 3

      Detection rules

      • Driver load (Sysmon EID 6 / MDE): Treat any load of ltmdm64.sys on a machine with no documented modem as suspicious. KQL: DeviceEvents | where ActionType == "DriverLoad" and FileName =~ "ltmdm64.sys". Sigma: logsource: windows/driver_load, ImageLoaded|endswith: '\ltmdm64.sys'.
      • Post-patch reintroduction (Sysmon EID 11, System 7045 / Security 4697): Watch for creation of ltmdm64.sys outside WinSxS servicing, or a new kernel service pointing at that file. On a patched host this strongly indicates BYOVD.
      • Process ancestry showing a privilege jump (Sysmon EID 1 / Security 4688): Look for a child process at IntegrityLevel=System whose parent runs as a medium-integrity standard user. Typical children are cmd.exe, powershell.exe, rundll32.exe or unsigned binaries from user paths. SPL starting point: index=sysmon EventCode=1 IntegrityLevel=System ParentUser!="NT AUTHORITY\\SYSTEM".
      • Follow-on activity: Correlate the events above with what tends to follow shortly after:
        • Security 4672 for unexpected accounts
        • LSASS access (Sysmon EID 10 with TargetImage ending in lsass.exe)
        • Local admin creation (4720/4732)
        • Defender tampering (Defender EID 5001)

    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

    Microsoft is aware of vulnerabilities in the third party Agere Modem driver that ships natively with supported Windows operating systems. This is an announcement of the upcoming removal of ltmdm64.sys driver. The driver has been removed in the October cumulative update. Fax modem hardware dependent on this specific driver will no longer work on Windows. Microsoft recommends removing any existing dependencies on this hardware.

    Source: NVD (NIST), CISA KEV Catalog, CVE.org (MITRE), pwn.watch, Microsoft Security Update Guide, 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 – < 10.0.10240.21161
    • 10.0.10240.21161
    MicrosoftWindows 10 Version 1607
    • 10.0.14393.0 – < 10.0.14393.8519
    • 10.0.14393.8519
    MicrosoftWindows 10 Version 1809
    • 10.0.17763.0 – < 10.0.17763.7919
    • 10.0.17763.7919
    MicrosoftWindows 10 Version 21H2
    • 10.0.19044.0 – < 10.0.19044.6456
    • 10.0.19044.6456
    MicrosoftWindows 10 Version 22H2
    • 10.0.19045.0 – < 10.0.19045.6456
    • 10.0.19045.6456
    MicrosoftWindows 11 version 22H2
    • 10.0.22621.0 – < 10.0.22621.6060
    • 10.0.22621.6060
    MicrosoftWindows 11 Version 23H2
    • 10.0.22631.0 – < 10.0.22631.6060
    • 10.0.22631.6060
    MicrosoftWindows 11 Version 24H2
    • 10.0.26100.0 – < 10.0.26100.6899
    • 10.0.26100.6899
    MicrosoftWindows 11 Version 25H2
    • 10.0.26200.0 – < 10.0.26200.6899
    • 10.0.26200.6899
    MicrosoftWindows Server 2008 R2 Service Pack 1
    • 6.1.7601.0 – < 6.1.7601.27974
    • 6.1.7601.27974
    MicrosoftWindows Server 2008 R2 Service Pack 1 (Server Core installation)
    • 6.1.7601.0 – < 6.1.7601.27974
    • 6.1.7601.27974
    MicrosoftWindows Server 2008 Service Pack 2
    • 6.0.6003.0 – < 6.0.6003.23571
    • 6.0.6003.23571
    MicrosoftWindows Server 2008 Service Pack 2 (Server Core installation)
    • 6.0.6003.0 – < 6.0.6003.23571
    • 6.0.6003.23571
    MicrosoftWindows Server 2012
    • 6.2.9200.0 – < 6.2.9200.25722
    • 6.2.9200.25722
    MicrosoftWindows Server 2012 (Server Core installation)
    • 6.2.9200.0 – < 6.2.9200.25722
    • 6.2.9200.25722
    MicrosoftWindows Server 2012 R2
    • 6.3.9600.0 – < 6.3.9600.22824
    • 6.3.9600.22824
    MicrosoftWindows Server 2012 R2 (Server Core installation)
    • 6.3.9600.0 – < 6.3.9600.22824
    • 6.3.9600.22824
    MicrosoftWindows Server 2016
    • 10.0.14393.0 – < 10.0.14393.8519
    • 10.0.14393.8519
    MicrosoftWindows Server 2016 (Server Core installation)
    • 10.0.14393.0 – < 10.0.14393.8519
    • 10.0.14393.8519
    MicrosoftWindows Server 2019
    • 10.0.17763.0 – < 10.0.17763.7919
    • 10.0.17763.7919
    MicrosoftWindows Server 2019 (Server Core installation)
    • 10.0.17763.0 – < 10.0.17763.7919
    • 10.0.17763.7919
    MicrosoftWindows Server 2022
    • 10.0.20348.0 – < 10.0.20348.4294
    • 10.0.20348.4294
    MicrosoftWindows Server 2022, 23H2 Edition (Server Core installation)
    • 10.0.25398.0 – < 10.0.25398.1913
    • 10.0.25398.1913
    MicrosoftWindows Server 2025
    • 10.0.26100.0 – < 10.0.26100.6899
    • 10.0.26100.6899
    MicrosoftWindows Server 2025 (Server Core installation)
    • 10.0.26100.0 – < 10.0.26100.6899
    • 10.0.26100.6899

    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_11_25h2—
    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-822Untrusted Pointer Dereference

      Base

      The product obtains a value from an untrusted source, converts this value to a pointer, and dereferences the resulting pointer.

      Entry at MITRE CWE-822

    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
    PoC-in-GitHub (nomi-sec)CVE-2025-24990 (opens in a new tab)github.comPoC (publicly reported)reported, not verified

    References & sources

    • Microsoft Security Update GuideWindows Agere Modem Driver Elevation of Privilege VulnerabilityVendor advisory, Patch, Vendor advisory
    • cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2025-24990government-resource, US government resource
    • vicarius.iovsociety/posts/cve-2025-24990-detection-script-elevation-of-pri…Third-party advisory
    • vicarius.iovsociety/posts/cve-2025-24990-mitigation-script-elevation-of-pr…Mitigation, Third-party advisory
    • pwn.watchpwn.watch: Microsoft Windows: 2 exploited vulnerabilities (CVE-2025-24990, CVE-2025-59230)pwn-watch
    • Microsoft Security Update GuideMicrosoft advisory: Microsoft Windowspwn-watch
    • Microsoft Security Update GuideMicrosoft advisory: Microsoft Windowspwn-watch
    • NVD (NIST)NVD: CVE-2025-24990pwn-watch
    • NVD (NIST)NVD: CVE-2025-59230pwn-watch
    • cisa.govCISA Known Exploited Vulnerabilities Catalogpwn-watch
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    Badge preview for CVE-2025-24990
    <a href="https://intel.neosec.eu/en/cve/CVE-2025-24990"><img src="https://intel.neosec.eu/badge/cve/CVE-2025-24990.svg?lang=en" alt="CVE-2025-24990 – NEOSEC Intel" height="20"></a>