IRONSMITHINTEL
HIGHCVSS7.8
|
Actively Exploited
|CISA KEV|CVE-2025-32701|Auth: low — local code execution required|Reboot: required|Est. 30–60 minutes including reboot|Manual only

KB5058379: Windows Server 2025, Windows Server 2022 +4 more Security Update (May 2025)

A local elevation-of-privilege vulnerability in the Windows Common Log File System (CLFS) kernel driver, exploited in the wild prior to disclosure. A local attacker with code execution on the host can gain SYSTEM. Patched in the May 13 2025 Patch Tuesday cumulative for every supported Windows Server / client SKU.

Published May 13, 2025 · Updated May 16, 2026
Why patchRisk explained in plain English
Worst-case scenarioIf unpatched

A non-administrator user (or a process running as a low-privilege service account) who can run code on the host can use this flaw to escalate to NT AUTHORITY\SYSTEM. This is a typical post-initial-access step in ransomware and APT operator playbooks: the attacker lands as a normal user (phishing, drive-by, web shell on an unprivileged service) and uses a CLFS EoP to gain the SYSTEM token needed to disable EDR, harvest credentials from LSASS, or move laterally.

How the attack worksNo clicks needed

CVE-2025-32701 is one of two CLFS driver EoP zero-days fixed in May 2025 (the second is CVE-2025-32706). CLFS exposes a kernel-mode logging subsystem to user-mode callers via documented Win32 APIs; flaws in how the driver validates log-file state allow a local attacker who can invoke those APIs to corrupt kernel memory and execute code at ring 0.

Am I affected?Quick check

Probably yes if any of these apply:

●All Windows Server hosts
●Hosts where unprivileged users can execute code
●Endpoints that have already been compromised (post-exploitation EoP)
●Running All supported Windows versions prior to the May 13 2025 cumulative update

Affected OS versions

Windows Server 2025Windows Server 2022Windows Server 2019Windows Server 2016Windows 11Windows 10
Fixed inKB5058379, KB5058383, KB5058384, KB5058385, KB5058387, KB5058392, KB5058403, KB5058405, KB5058411, KB5058429, KB5058430, KB5058449, KB5058451, KB5058454, KB5058497, KB5058500 (applies to 37 product versions) — build 10.0.10240.21014, 10.0.14393.8066+
Real-world incidentsWhat we've seen

Microsoft flagged CVE-2025-32701 as Exploitation Detected at the May 13 2025 release. The CLFS driver has been a recurring target throughout 2025 — Microsoft also patched CVE-2025-29824 (CLFS EoP, exploited by Storm-2460 / PipeMagic) in the April 2025 Patch Tuesday, making May 2025 the third month with in-the-wild CLFS EoP fixes.

How to patch

Manual download

For air-gapped servers or out-of-band deployment. Microsoft Update Catalog returns every OS-version variant of this update.

↗ Microsoft Update CatalogKB5058379

Manual remediation steps

⏱ 30–60 minutes including reboot

Apply the Microsoft Security Update

Microsoft has released an official security update that fixes this vulnerability.

Required KB Updates

    1
    KB5058379 — https://support.microsoft.com/help/5058379
    1
    KB5058383 — https://support.microsoft.com/help/5058383
    1
    KB5058384 — https://support.microsoft.com/help/5058384
    1
    KB5058385 — https://support.microsoft.com/help/5058385
    1
    KB5058387 — https://support.microsoft.com/help/5058387
    1
    KB5058392 — https://support.microsoft.com/help/5058392
    1
    KB5058403 — https://support.microsoft.com/help/5058403
    1
    KB5058405 — https://support.microsoft.com/help/5058405
    1
    KB5058411 — https://support.microsoft.com/help/5058411
    1
    KB5058429 — https://support.microsoft.com/help/5058429
    1
    KB5058430 — https://support.microsoft.com/help/5058430
    1
    KB5058449 — https://support.microsoft.com/help/5058449
    1
    KB5058451 — https://support.microsoft.com/help/5058451
    1
    KB5058454 — https://support.microsoft.com/help/5058454
    1
    KB5058497 — https://support.microsoft.com/help/5058497
    1
    KB5058500 — https://support.microsoft.com/help/5058500

Supersedes: KB5055518, KB5055519, KB5055521, KB5055523, KB5055526, KB5055527, KB5055528, KB5055547, KB5055557, KB5055561, KB5055581, KB5055609

Affected Products

    1
    Windows 10 Version 1607 for 32-bit Systems
    1
    Windows 10 Version 1607 for x64-based Systems
    1
    Windows 10 Version 1809 for 32-bit Systems
    1
    Windows 10 Version 1809 for x64-based Systems
    1
    Windows 10 Version 21H2 for 32-bit Systems
    1
    Windows 10 Version 21H2 for ARM64-based Systems
    1
    Windows 10 Version 21H2 for x64-based Systems
    1
    Windows 10 Version 22H2 for 32-bit Systems
    1
    Windows 10 Version 22H2 for ARM64-based Systems
    1
    Windows 10 Version 22H2 for x64-based Systems
    1
    Windows 10 for 32-bit Systems
    1
    Windows 10 for x64-based Systems
    1
    Windows 11 Version 22H2 for ARM64-based Systems
    1
    Windows 11 Version 22H2 for x64-based Systems
    1
    Windows 11 Version 23H2 for ARM64-based Systems
    1
    Windows 11 Version 23H2 for x64-based Systems
    1
    Windows 11 Version 24H2 for ARM64-based Systems
    1
    Windows 11 Version 24H2 for x64-based Systems
    1
    Windows Server 2008 R2 for x64-based Systems Service Pack 1
    1
    Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)
    1
    (…17 more product versions)

Fixed Build Numbers

    1
    10.0.10240.21014
    1
    10.0.14393.8066
    1
    10.0.17763.7314
    1
    10.0.19044.5854
    1
    10.0.19045.5854
    1
    10.0.20348.3630
    1
    10.0.20348.3692
    1
    10.0.22621.5335
    1
    10.0.22631.5335
    1
    10.0.25398.1611
    1
    (…6 more builds)

Installation Methods

Windows Update (recommended)

1
Settings → Windows Update → Check for updates
2
The security update is offered if your system is in scope
3
Restart when prompted — a reboot IS required to complete the install

Microsoft Update Catalog (manual download)

1
Open https://catalog.update.microsoft.com
2
Search for KB5058379
3
Download the package matching your OS architecture and Windows build
4
Run the .msu installer with administrator privileges
5
Restart when prompted

WSUS / SCCM / Intune

Approve KB5058379 for the affected products in your update management console.

Microsoft Download Center Links

    1
    https://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB5058379
    1
    https://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB5058383
    1
    https://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB5058384
    1
    https://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB5058385
    1
    https://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB5058387
    1
    (…11 more)

Verification

Confirm the update is installed:

Get-HotFix | Where-Object { $_.HotFixID -in @('KB5058379','KB5058383','KB5058384','KB5058385','KB5058387','KB5058392','KB5058403','KB5058405','KB5058411','KB5058429','KB5058430','KB5058449','KB5058451','KB5058454','KB5058497','KB5058500') }

References

    1
    Microsoft Security Response Center: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-32701
    1
    KB article: https://support.microsoft.com/help/5058379
    1
    KB article: https://support.microsoft.com/help/5058383
    1
    KB article: https://support.microsoft.com/help/5058384
    1
    NVD entry: https://nvd.nist.gov/vuln/detail/CVE-2025-32701
    1
    CISA KEV: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-32701

Discovery Credit

Microsoft Threat Intelligence Center

PowerShell automationComing soon

No tested PowerShell script for this entry yet. We’re prioritising automation based on user demand.

References

↗ CVE-2025-32701↗ MSRC Advisory↗ NVD↗ KBKB5058379