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CVE-2026-26170 Microsoft CVE debrief

Microsoft PowerShell Elevation of Privilege Vulnerability allows an authorized attacker to elevate privileges locally due to improper input validation. Multiple Windows versions and server releases are affected. The vulnerability is caused by improper input validation in Microsoft PowerShell, which can be exploited by an authorized attacker to elevate privileges locally. Affected systems include Windows 10 Version 1607, Windows 10 Version 1809, Windows 10 Version 21H2, Windows 10 Version 22H2, Windows 11 version 23H2, Windows 11 Version 23H2, Windows 11 Version 24H2, Windows 11 Version 25H2, Windows 11 version 26H1, Windows Server 2016, Windows Server 2016 (Server Core installation

Vendor
Microsoft
Product
Windows 10 Version 1607
CVSS
HIGH 7.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-04-14
Original CVE updated
2026-10-15
Advisory published
2026-04-14
Advisory updated
2026-10-15

Who should care

Defenders responsible for Windows and Windows Server systems, especially those with high-risk exposure, should prioritize patching affected versions.

Why it matters

CVE-2026-26170 is a high-severity elevation of privilege vulnerability in Microsoft PowerShell. Defenders should prioritize patching affected Windows and Windows Server systems.

  • Local privilege escalation is possible for authorized attackers
  • Patching is required to prevent exploitation
  • Verify system configurations and inventory for affected versions
  • Monitor for potential local privilege escalation attempts

Technical summary

The PowerShell Elevation of Privilege Vulnerability (CVE-2026-26170) is caused by improper input validation in Microsoft PowerShell. An authorized attacker can exploit this vulnerability to elevate privileges locally. The vulnerability affects multiple versions of Windows 10, Windows 11, and Windows Server, including Windows 10 Version 1607, Windows 10 Version 1809, Windows 10 Version 21H2, Windows 10 Version 22H2, Windows 11 version 23H2, Windows 11 Version 23H2, Windows 11 Version 24H2, Windows 11 Version 25H2, Windows 11 version 26H1, Windows Server 2016, Windows Server 2016 (Server Core installation), Windows Server 2019, Windows Server 2019 (Server Core installation), Windows Server 2022, Windows Server 2022, 23H2 Edition (Server Core installation), Windows Server 2025, and Windows Server 2025 (Server Core installation).

Defensive priority

Defenders should prioritize patching affected Windows and Windows Server systems, especially those with high-risk exposure.

Recommended defensive actions

  • Patch affected Windows 10, Windows 11, and Windows Server versions
  • Verify system configurations and inventory for affected versions
  • Monitor for potential local privilege escalation attempts

Evidence notes

The CVE record and source item provide details on the vulnerability and affected systems. Microsoft's official advisory is referenced. The vulnerability affects multiple versions of Windows 10, Windows 11, and Windows Server. The CVE record was published on 2026-04-14T16:57:59.294Z and has not been modified since then. The source item details are also provided. The official CVE Program record and NIST NVD vulnerability detail are referenced.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-26170 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-26170

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-26170 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-26170

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • PowerShell Elevation of Privilege Vulnerability

    Unverified legacy reference

    URL: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/26xxx/CVE-2026-26170.json

    cve_program_cvelist_v5

  • Source reference

    Unverified legacy reference

    URL: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-26170

    Supplemental source - vendor-advisory, patch

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.