SecOps SignalSecurity Intelligence Workspace
Loading collection status
Vulnerabilities/CVE-2026-77891Public Intelligence Dossier
Source: Microsoft · Limited verification•Last verified: •Collection Degraded
CVE-2026-77891Unknown / EvaluatingImportant (raw)CVSS 6.4

Windows DHCP Server Remote Code Execution Vulnerability

Published: 08 Sept 2026•Last updated: 08 Sept 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
6.4Important (raw)
CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
Metric sourceMicrosoft MSRC CVRF
EPSS probability
0.3%0.003
Percentile19th
Weakness type
—
No further CWE recorded
Remediation
Patch status unknown
KB5122876, KB5122882, KB5122871, KB5123099, KB5123065, KB5123066

Why It Matters

Analysis dossier

Why It Matters

Out-of-bounds read in Windows DHCP Server allows an authorized attacker to execute code locally.

SOC priority

Medium

Actively exploited

No

Publicly disclosed

Unknown

Risk basis: No confirmed exploitation signal in current enrichment

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 / KBKB5122876, KB5122882, KB5122871, KB5123099, KB5123065, KB5123066

Vendor or catalog guidance (source)

  • Microsoft MSRC: Install the security update KB5122876 listed by MSRC
  • Microsoft MSRC: Install the security update KB5122882 listed by MSRC
  • Microsoft MSRC: Install the security update KB5122871 listed by MSRC
  • Microsoft MSRC: Install the security update KB5123099 listed by MSRC
  • Microsoft MSRC: Install the security update KB5123065 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)

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

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

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
Detection Hunting Query

— No published hunting query names this record. Browse community and library queries instead.

Open KQL Library
Loading related intelligence

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.