CVE-2026-50458Public exploit

Local privilege escalation via directory-cache race

Published Jul 14, 2026 · Updated Jul 14, 2026

Use-after-free in Microsoft Brokering File System on affected Windows releases allows local users to elevate privileges through a race condition. BfsInsertDirectory returns an existing AVL directory-cache entry without incrementing its reference count when concurrent requests insert the same path component. A medium-integrity process can race four or more set-policy IOCTL requests, causing premature object release and stale kernel-memory use that supports privilege elevation or a system crash.

CVSS severity7.8
High
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Microsoft Brokering File System on affected Windows releases allows local users to elevate privileges through a race condition. BfsInsertDirectory returns an existing AVL directory-cache entry without incrementing its reference count when concurrent requests insert the same path component. A medium-integrity process can race four or more set-policy IOCTL requests, causing premature object release and stale kernel-memory use that supports privilege elevation or a system crash.

The record

CVE
CVE-2026-50458
Published
Jul 14, 2026
Updated
Jul 14, 2026
Vendor
Microsoft
Product
Windows Server 2025 (Server Core installation)
Classifications
CWE-362, CWE-416, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 14, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.0.26100.0 <10.0.26100.33158

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Microsoft · Windows Server 2025 (Server Core installation)version=10.0.26100.0 <10.0.26100.33158
Microsoft · Windows 11, version 25H2version=10.0.26200.0 <10.0.26200.8875
Microsoft · Windows 11, version 24H2version=10.0.26100.0 <10.0.26100.8875
Microsoft · Windows 11, version 26H1version=10.0.28000.0 <10.0.28000.2269
Microsoft · Windows Server 2025version=10.0.26100.0 <10.0.26100.33158

Published CVSS scores

7.8Microsoft CorporationCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
CWE-416Use After Free
T1068Exploitation for Privilege Escalation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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