CVE-2026-85921

Local privilege escalation via double free

Published Sep 14, 2026 · Updated Sep 14, 2026

Double free in Microsoft Windows 11 version 26H1 Secure Kernel Mode allows local users to elevate privileges on affected systems. Secure Kernel Mode releases the same memory allocation twice, but Microsoft has not disclosed the affected object or trigger path. Exploitation requires authorized local access and can cross the local privilege boundary; no remotely reachable trigger is reported.

CVSS severityUnavailable
Unscored
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

Double free in Microsoft Windows 11 version 26H1 Secure Kernel Mode allows local users to elevate privileges on affected systems. Secure Kernel Mode releases the same memory allocation twice, but Microsoft has not disclosed the affected object or trigger path. Exploitation requires authorized local access and can cross the local privilege boundary; no remotely reachable trigger is reported.

The record

CVE
CVE-2026-85921
Published
Sep 14, 2026
Updated
Sep 14, 2026
Vendor
Microsoft
Product
Windows 11, version 26H1
Classifications
CWE-415, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 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=10.0.28000.0 <10.0.28000.2956

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Microsoft · Windows 11, version 26H1version=10.0.28000.0 <10.0.28000.2956

Published CVSS scores

No CVSS assessment is available in this record.

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-415Double Free
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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