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Windows 11 23h2Operating system · Microsoft

CVE-2026-26181

HIGH · 7.8 CVSS v3.1 Published 2026-04-14
Fix available
A fix is available. Upgrade to 10.0.22631.6936 / 10.0.25398.2274 or later.
See remediation →
80/100
Remediation priority · High
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Use after free in Microsoft Brokering File System allows an authorized attacker to elevate privileges locally.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

A use-after-free vulnerability in Microsoft Brokering File System allows a locally authenticated attacker to manipulate freed memory and escalate privileges to higher integrity levels.

MitigationApply Microsoft security updates for this vulnerability when released; until then, restrict local system access to privileged users only and monitor for indicators of local privilege escalation attempts.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Windows 11 23h2Operating system
Affected:< 10.0.22631.6936
Windows 11 24h2Operating system
Affected:< 10.0.26100.8246
Windows 11 25h2Operating system
Affected:< 10.0.26200.8246
Windows 11 26h1Operating system
Affected:< 10.0.28000.1836
Windows Server 2022 23h2Operating system
Affected:< 10.0.25398.2274
Windows Server 2025Operating system
Affected:< 10.0.26100.32690

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check Windows version against affected ranges
    Run 'winver' or 'systeminfo | findstr /B /C:"OS Name" /C:"OS Version"' to obtain the exact build number, then compare to the affected version thresholds (22631.6936, 26100.8246, 26200.8246, 28000.1836, 25398.2274, 26100.32690 depending on edition)
    Affected if The installed build number is lower than the corresponding threshold for your Windows edition
  2. Verify local user authentication is possible
    Run 'net user' to enumerate local user accounts, and check user rights with 'whoami /all' to confirm accounts have logon capability
    Affected if Local user accounts exist with interactive logon rights, providing an attack surface for the vulnerability
  3. Confirm the Brokering File System component is present
    Check for the presence of the Brokering File System driver by examining loaded kernel modules via 'fltmc filters' or reviewing 'msinfo32' kernel sections for filesystem-related components
    Affected if The Brokering File System component is loaded or available on the system, which is required for exploitation
  4. Audit recent privilege escalation indicators
    Review Windows Security event logs (Event IDs 4624, 4672, 4688) for unexpected account privilege assignments or new process creation by low-integrity users
    Affected if Audit logs show unusual privilege escalation activity or creation of processes running at higher integrity levels by standard users

A system is affected if it runs a Windows version below the listed thresholds AND has local user accounts that could trigger the use-after-free in the Brokering File System component.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 10.0.22631.6936 / 10.0.25398.2274 / 10.0.26100.8246 or later
Fixed in 10.0.22631.693610.0.25398.227410.0.26100.8246
Interim mitigation

Apply Microsoft security updates for this vulnerability when released; until then, restrict local system access to privileged users only and monitor for indicators of local privilege escalation attempts.

Recommended fix High confidence

Windows 11 23h2: build 10.0.22631.6936 or later | Windows 11 24h2: build 10.0.26100.8246 or later | Windows 11 25h2: build 10.0.26200.8246 or later | Windows 11 26h1: build 10.0.28000.1836 or later | Windows Server 2022 23h2: build 10.0.25398.2274 or later | Windows Server 2025: build 10.0.26100.326

  1. Identify the current Windows build version by running 'winver' or 'systeminfo' in Command Prompt
  2. Determine which Windows version and build family applies to your system (11 23h2, 11 24h2, 11 25h2, 11 26h1, Server 2022 23h2, or Server 2025)
  3. Apply the appropriate Windows security update that includes the fix for CVE-2026-26181
  4. Verify the installation was successful by checking the new build version matches or exceeds the fixed release for your version
Caveat Standard Windows update; no expected breaking changes for this security patch

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Windows 11 23h2 Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,060
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Scan for this in your stack

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-26181 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data