CVE-2026-78457

Local privilege escalation via use-after-free

Published Sep 8, 2026 · Updated Sep 9, 2026

Use-after-free in Windows Security Health Service on affected Windows releases allows local users to elevate privileges. Microsoft identifies the service-level memory lifetime flaw but has not disclosed the affected function, freed object, or trigger sequence. Successful exploitation requires low-privileged local access and a complex trigger, after which the attacker gains elevated privileges.

CVSS severity7.0
High
EPSS probability0.20%
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 Windows Security Health Service on affected Windows releases allows local users to elevate privileges. Microsoft identifies the service-level memory lifetime flaw but has not disclosed the affected function, freed object, or trigger sequence. Successful exploitation requires low-privileged local access and a complex trigger, after which the attacker gains elevated privileges.

The record

CVE
CVE-2026-78457
Published
Sep 8, 2026
Updated
Sep 9, 2026
Vendor
Microsoft
Product
Windows Server 2025 (Server Core installation)
Classifications
CWE-416, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 9, 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 <10.0.26100.33438

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Microsoft · Windows Server 2025 (Server Core installation)version=10.0.26100.0 <10.0.26100.33438
Microsoft · Windows 11, version 25H2version=10.0.26200.0 <10.0.26200.9445
Microsoft · Windows 11, version 24H2version=10.0.26100.0 <10.0.26100.9445
Microsoft · Windows 11, version 26H1version=10.0.28000.0 <10.0.28000.2954
Microsoft · Windows Server 2022version=10.0.20348.0 <10.0.20348.5622
Microsoft · Windows Server 2025version=10.0.26100.0 <10.0.26100.33438

Published CVSS scores

7.0MicrosoftCVSS: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-416Use After 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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