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Vulnerabilities/CVE-2026-85884Public Intelligence Dossier
Source: Microsoft · Limited verification•Last verified: •Collection Degraded
CVE-2026-85884Unknown / EvaluatingImportant (raw)CVSS 7.8CWE-306

Windows Health and Optimized Experiences Service Elevation of Privilege Vulnerability

Published: 13 Oct 2026•Last updated: 13 Oct 2026, 12:30 PM IST•Source identifier: secure@microsoft.com
Dossier completeness: source-provided sections 3 / 3 · rule guidance available. Missing source facts count as incomplete.
Official source
CISA KEV catalog
Unknown
KEV status was not determined.
CVSS score
7.8Important (raw)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
Metric sourceMicrosoft MSRC CVRF
EPSS probability
0.4%0.004
Percentile32nd
Weakness type
CWE-306
No further CWE recorded
Remediation
Patch status unknown
KB5127648, KB5127646

Why It Matters

Analysis dossier

Why It Matters

Missing authentication for critical function in Windows Health and Optimized Experiences Service allows an authorized attacker to elevate privileges locally.

SOC priority

Review

Actively exploited

No

Publicly disclosed

Unknown

Risk basis: Microsoft or Microsoft-managed product relevance; HIGH severity

Affected Products & Remediation

8 source-backed products
Affected products and versions (source)
  • Windows 11 Version 25H2 for ARM64-based Systems · version range not provided by source · Microsoft MSRC · Source
  • Windows 11 Version 25H2 for x64-based Systems · version range not provided by source · Microsoft MSRC · Source
  • Windows 11 Version 24H2 for ARM64-based Systems · version range not provided by source · Microsoft MSRC · Source
  • Windows 11 Version 24H2 for x64-based Systems · version range not provided by source · Microsoft MSRC · Source
  • Windows 11 version 26H1 for x64-based Systems · version range not provided by source · Microsoft MSRC · Source
  • Windows 11 Version 26H1 for ARM64-based Systems · version range not provided by source · Microsoft MSRC · Source
  • Windows 11 Version 26H2 for ARM64-based Systems · version range not provided by source · Microsoft MSRC · Source
  • Windows 11 Version 26H2 for x64-based Systems · version range not provided by source · Microsoft MSRC · Source
Recorded patch / KBKB5127648, KB5127646

Vendor or catalog guidance (source)

  • Microsoft MSRC: Install the security update KB5127648 listed by MSRC
  • Microsoft MSRC: Install the security update KB5127646 listed by MSRC

Known exploitation (source facts)

Only what a source states. Unknown means no source has said either way; it is not "not exploited".

CISA KEV
Unknown
Exploited (source statement)
No
Publicly disclosed (source)
Unknown

Suggested hunting (rule-based inference)

SecOps Signal recommendation (rule-based inference). These steps are hunting hypotheses from the vulnerability class; they do not state or imply that exploitation occurred here or anywhere.

Matched microsoft-enterprise (Affected product: Windows 11 Version 25H2 for ARM64-based Systems, Vendor: Microsoft); authentication-weakness (CWE-306)

Exposure

  1. Identify affected Microsoft products and compare local builds with the MSRC advisory.Telemetry: DeviceTvmSoftwareVulnerabilities · The MSRC product/build mapping establishes applicability. · Rule microsoft-enterprise
  2. Identify affected authentication surfaces and compare versions with the advisory.Telemetry: Application inventory · A CWE match is not proof of local exposure. · Rule authentication-weakness

Exploitation evidence

  1. Review the advisory's documented behavior on matching hosts before selecting a hunt.Telemetry: DeviceProcessEvents · Product family alone does not justify a CVE-specific detection. · Rule microsoft-enterprise
Show more (2)

Exploitation evidence

  1. Review unexpected successful sign-ins and changes to privileged accounts on affected systems.Telemetry: SigninLogs · Access anomalies are relevant to authentication weaknesses. · Rule authentication-weakness

Response

  1. Confirm the source-stated KB or mitigation on matching assets.Telemetry: DeviceTvmSoftwareVulnerabilities · A post-update inventory check verifies remediation. · Rule microsoft-enterprise

CISA KEV Record

CISA KEV status was not determined for this record.

Change History & Source Data

— No recorded material change

CNA / source
secure@microsoft.com
Record status · verification
UPDATED · Unknown
CPE
Unknown

Evidence & Provenance

3 public sources
api.msrc.microsoft.comSource recordnvd.nist.govSource recordmsrc.microsoft.comSource record

Linked by the query's stored exact CVE association. Review required tables and validation status before use.

Detection Hunting Query
Target: DeviceTvmSoftwareVulnerabilities•Defender XDR
Detect endpoints exposed to CVE-2026-85884
Purpose: Exposure assessment (Category: Exposure Check)Why linked: Query metadata names CVE-2026-85884
DeviceTvmSoftwareVulnerabilities| where CveId == "CVE-2026-85884"| project DeviceId, DeviceName, OSPlatform, OSVersion, SoftwareVendor, SoftwareName, SoftwareVersion, CveId, VulnerabilitySeverityLevel, RecommendedSecurityUpdate, RecommendedSecurityUpdateId| sort by VulnerabilitySeverityLevel desc
Schema Checked · Not runtime validatedSource: SecOps Signal deterministic template · Limited verificationStatic screening: Passed structure and schema checks; tenant execution is not verified.
Open KQL Library

Correlated briefings

Microsoft Security Update Guide · Limited verificationOctober 2026 Security UpdatesPublished 13 Oct 2026
SecOps Signal surfaces public advisory facts only. A missing value means the source has not published it, not that your environment is unaffected. No tenant inventory is connected.