Source: Microsoft · Limited verification•Last verified: •Collection Degraded
CVE-2026-96858Unknown / EvaluatingImportant (raw)CVSS 5.5CWE-306
Windows Security Account Manager Tampering 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.
CISA KEV catalog
Unknown
KEV status was not determined.
CVSS score
5.5Important (raw)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N/E:U/RL:O/RC:C
Metric sourceMicrosoft MSRC CVRF
EPSS probability
0.4%0.004
Percentile27th
Weakness type
CWE-306
No further CWE recorded
Remediation
Patch status unknown
KB5126657, KB5126655, KB5126653, KB5127648, KB5126646, KB5127646
Why It Matters
Analysis dossierWhy It Matters
Missing authentication for critical function in Windows Security Account Manager allows an authorized attacker to perform tampering locally.
SOC priority
Medium
Actively exploited
No
Publicly disclosed
Unknown
Risk basis: Microsoft or Microsoft-managed product relevance; No confirmed exploitation signal in current enrichment
Affected Products & Remediation
20 source-backed productsAffected products and versions (source)
- Windows 10 Version 21H2 for 32-bit Systems · version range not provided by source · Microsoft MSRC · Source
- Windows 10 Version 21H2 for ARM64-based Systems · version range not provided by source · Microsoft MSRC · Source
- Windows 10 Version 21H2 for x64-based Systems · version range not provided by source · Microsoft MSRC · Source
- Windows 10 Version 22H2 for 32-bit Systems · version range not provided by source · Microsoft MSRC · Source
- Windows 10 Version 22H2 for ARM64-based Systems · version range not provided by source · Microsoft MSRC · Source
- Windows 10 Version 22H2 for x64-based Systems · version range not provided by source · Microsoft MSRC · Source
- Windows Server 2022 · version range not provided by source · Microsoft MSRC · Source
- Windows Server 2022 (Server Core installation) · version range not provided by source · Microsoft MSRC · Source
- Windows 11 Version 23H2 for ARM64-based Systems · version range not provided by source · Microsoft MSRC · Source
- Windows 11 Version 23H2 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 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 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
- Windows Server 2025 · version range not provided by source · Microsoft MSRC · Source
- Windows Server 2025 (Server Core installation) · 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 26H1 for x64-based Systems · version range not provided by source · Microsoft MSRC · Source
Recorded patch / KBKB5126657, KB5126655, KB5126653, KB5127648, KB5126646, KB5127646
Vendor or catalog guidance (source)
- Microsoft MSRC: Install the security update KB5126657 listed by MSRC
- Microsoft MSRC: Install the security update KB5126655 listed by MSRC
- Microsoft MSRC: Install the security update KB5126653 listed by MSRC
- Microsoft MSRC: Install the security update KB5127648 listed by MSRC
- Microsoft MSRC: Install the security update KB5126646 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 10 Version 21H2 for 32-bit Systems, Vendor: Microsoft); authentication-weakness (CWE-306)
Exposure
- Identify affected Microsoft products and compare local builds with the MSRC advisory.Telemetry: DeviceTvmSoftwareVulnerabilities · The MSRC product/build mapping establishes applicability. · Rule microsoft-enterprise
- 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
- 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
- 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
- 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
Detection Hunting Query
— No published hunting query names this record. Browse community and library queries instead.
Correlated briefings
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.