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Vulnerabilities/CVE-2026-70005Public Intelligence Dossier
Source: Microsoft · Limited verification•Last verified: •Collection Degraded
CVE-2026-70005Unknown / EvaluatingImportant (raw)CVSS 5.9CWE-1390

Active Directory Federation Services (AD FS) Security Feature Bypass 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
5.9Important (raw)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N/E:U/RL:O/RC:C
Metric sourceMicrosoft MSRC CVRF
EPSS probability
0.6%0.006
Percentile46th
Weakness type
CWE-1390
No further CWE recorded
Remediation
Patch status unknown
KB5126651, KB5126655, KB5126646

Why It Matters

Analysis dossier

Why It Matters

Weak authentication in Active Directory Federation Services (AD FS) allows an unauthorized attacker to bypass a security feature over a network.

SOC priority

Review

Actively exploited

No

Publicly disclosed

Unknown

Risk basis: Microsoft or Microsoft-managed product relevance

Affected Products & Remediation

6 source-backed products
Affected products and versions (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 · version range not provided by source · Microsoft MSRC · Source
  • Windows Server 2025 (Server Core installation) · version range not provided by source · Microsoft MSRC · Source
Recorded patch / KBKB5126651, KB5126655, KB5126646

Vendor or catalog guidance (source)

  • Microsoft MSRC: Install the security update KB5126651 listed by MSRC
  • Microsoft MSRC: Install the security update KB5126655 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 Server 2019, 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
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-2026-70005
Purpose: Exposure assessment (Category: Exposure Check)Why linked: Query metadata names CVE-2026-70005
DeviceTvmSoftwareVulnerabilities| where CveId == "CVE-2026-70005"| 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.