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Vulnerabilities/CVE-2026-65791Public Intelligence Dossier
Source: Microsoft · Limited verification•Last verified: •Collection Degraded
CVE-2026-65791Unknown / EvaluatingCritical (raw)CVSS 9.8

Windows iSCSI Target Service Remote Code Execution Vulnerability

Published: 11 Aug 2026•Last updated: 06 Oct 2026, 12:30 PM IST•Source identifier: Unknown
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
9.8Critical (raw)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
Metric sourceMicrosoft MSRC CVRF
EPSS probability
1%0.010
Percentile61st
Weakness type
—
No further CWE recorded
Remediation
Patch status unknown
KB5120238, KB5120242, KB5120229, KB5120233, KB5120228, KB5120418, KB5120386, KB5120385

Why It Matters

Analysis dossier

Why It Matters

Heap-based buffer overflow in Windows iSCSI Target Service allows an unauthorized attacker to execute code over a network.

SOC priority

High Severity / Review

Actively exploited

No

Publicly disclosed

Unknown

Risk basis: Critical CVSS without confirmed KEV exploitation

Affected Products & Remediation

16 source-backed products
Affected products and versions (source)
  • Windows 10 Version 1809 for 32-bit Systems · version range not provided by source · Microsoft MSRC · Source
  • Windows 10 Version 1809 for x64-based Systems · version range not provided by source · Microsoft MSRC · Source
  • Windows Server 2019 · version range not provided by source · Microsoft MSRC · Source
  • Windows Server 2019 (Server Core installation) · 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 Server 2025 (Server Core installation) · version range not provided by source · Microsoft MSRC · Source
  • Windows Server 2025 · version range not provided by source · Microsoft MSRC · Source
  • Windows 10 Version 1607 for 32-bit Systems · version range not provided by source · Microsoft MSRC · Source
  • Windows 10 Version 1607 for x64-based Systems · version range not provided by source · Microsoft MSRC · Source
  • Windows Server 2016 · version range not provided by source · Microsoft MSRC · Source
  • Windows Server 2016 (Server Core installation) · version range not provided by source · Microsoft MSRC · Source
  • Windows Server 2012 · version range not provided by source · Microsoft MSRC · Source
  • Windows Server 2012 (Server Core installation) · version range not provided by source · Microsoft MSRC · Source
  • Windows Server 2012 R2 · version range not provided by source · Microsoft MSRC · Source
  • Windows Server 2012 R2 (Server Core installation) · version range not provided by source · Microsoft MSRC · Source
Recorded patch / KBKB5120238, KB5120242, KB5120229, KB5120233, KB5120228, KB5120418, KB5120386, KB5120385

Vendor or catalog guidance (source)

  • Microsoft MSRC: Install the security update KB5120238 listed by MSRC
  • Microsoft MSRC: Install the security update KB5120242 listed by MSRC
  • Microsoft MSRC: Install the security update KB5120229 listed by MSRC
  • Microsoft MSRC: Install the security update KB5120233 listed by MSRC
  • Microsoft MSRC: Install the security update KB5120228 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 1809 for 32-bit Systems, Vendor: Microsoft); network-unauthenticated (CVSS AV:N, CVSS PR:N, CVSS UI:N)

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 devices reporting this CVE and note which expose the affected service to untrusted networks.Telemetry: DeviceTvmSoftwareVulnerabilities · A network-reachable, no-privilege vector makes internet-facing instances the first exposure question. · Rule network-unauthenticated

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 inbound connections to the affected service from unexpected sources since the advisory date.Telemetry: DeviceNetworkEvents · Hunting hypothesis from the CVSS vector; it does not show that exploitation occurred. · Rule network-unauthenticated

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
Unknown
Record status · verification
UPDATED · Unknown
CPE
Unknown

Evidence & Provenance

1 public source
api.msrc.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-2026-65791
Purpose: Exposure assessment (Category: Exposure Check)Why linked: Query metadata names CVE-2026-65791
DeviceTvmSoftwareVulnerabilities| where CveId == "CVE-2026-65791"| 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 verificationAugust 2026 Security UpdatesPublished 11 Aug 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.