CVE-2026-45487

Local privilege escalation via undisclosed TOCTOU race

Published Jun 9, 2026 · Updated Jun 9, 2026

A TOCTOU race in Microsoft Windows Program Compatibility Assistant Service allows local users to elevate privileges on affected builds. Microsoft has not disclosed the resource whose state is checked and later used, or the specific operation that loses synchronization. A low-privileged local session and running Program Compatibility Assistant Service are required; exploitation grants higher Windows privileges.

CVSS severity7.8
High
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A TOCTOU race in Microsoft Windows Program Compatibility Assistant Service allows local users to elevate privileges on affected builds. Microsoft has not disclosed the resource whose state is checked and later used, or the specific operation that loses synchronization. A low-privileged local session and running Program Compatibility Assistant Service are required; exploitation grants higher Windows privileges.

The record

CVE
CVE-2026-45487
Published
Jun 9, 2026
Updated
Jun 9, 2026
Vendor
Microsoft
Product
Windows Server 2025 (Server Core installation)
Classifications
CWE-367, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

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 <10.0.26100.32995

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Microsoft · Windows Server 2025 (Server Core installation)version=10.0.26100.0 <10.0.26100.32995
Microsoft · Windows 11, version 25H2version=10.0.26200.0 <10.0.26200.8655
Microsoft · Windows 11, version 24H2version=10.0.26100.0 <10.0.26100.8655
Microsoft · Windows 10 Version 21H2version=10.0.19044.0 <10.0.19044.7417
Microsoft · Windows 10 Version 22H2version=10.0.19045.0 <10.0.19045.7417
Microsoft · Windows 11, version 26H1version=10.0.28000.0 <10.0.28000.2269
Microsoft · Windows 11 Version 23H2version=10.0.22631.0 <10.0.22631.7219
Microsoft · Windows Server 2022version=10.0.20348.0 <10.0.20348.5256
Microsoft · Windows Server 2025version=10.0.26100.0 <10.0.26100.32995

Published CVSS scores

7.8MicrosoftCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.0NIST NVDCVSS:3.1/AV:L/AC:H/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 exploitUnconfirmed

Weakness, pattern, technique

CWE-367Time-of-check Time-of-use (TOCTOU) Race Condition
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

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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