Windows Advanced Local Procedure Call (ALPC) Elevation of Privilege Vulnerability
Why It Matters
Analysis dossierWhy It Matters
Heap-based buffer overflow in Windows ALPC allows an authorized attacker to elevate privileges locally.
Immediate Attention
Yes
Unknown
Risk basis: Known exploitation signal from CISA KEV or ransomware metadata
Affected Products & Remediation
20 source-backed products- 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 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 x64-based 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 32-bit Systems · 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
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 KB5122878 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
- Listed
- Exploited (source statement)
- Yes
- Publicly disclosed (source)
- Unknown
CISA required action: Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
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); local-privilege-escalation (CVSS AV:L, CVSS PR:L)
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 hosts reporting this CVE, prioritising shared or multi-user systems.Telemetry: DeviceTvmSoftwareVulnerabilities · A local, low-privilege vector matters most where untrusted users can run code. · Rule local-privilege-escalation
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
- Look for low-privileged processes spawning SYSTEM or root-level child processes on affected hosts.Telemetry: DeviceProcessEvents · Hunting hypothesis from the CVSS vector; privilege transitions are a focused starting point, not evidence of attack. · Rule local-privilege-escalation
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
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
Change History & Source Data
— No recorded material change
- CNA / source
- Unknown
- Record status · verification
- UPDATED · Microsoft primary source linked; CISA KEV confirmed
- CPE
- Unknown
Evidence & Provenance
Linked by the query's stored exact CVE association. Review required tables and validation status before use.
DeviceTvmSoftwareVulnerabilities| where CveId == "CVE-2026-85880"| project DeviceId, DeviceName, OSPlatform, OSVersion, SoftwareVendor, SoftwareName, SoftwareVersion, CveId, VulnerabilitySeverityLevel, RecommendedSecurityUpdate, RecommendedSecurityUpdateId| sort by VulnerabilitySeverityLevel desc