Windows PowerShell: Security feature bypass through protection mechanism failure
Summary
A protection mechanism failure in Windows PowerShell allows an authorized local user to bypass a security feature. The CVSS score of 8.8 reflects a scope change and high impact on confidentiality, integrity and availability. The attacker needs a valid local low-privilege account, so the flaw is mainly a follow-on step after another compromise, such as phishing or a stolen password.
Affected
- Windows 10 Version 1607 (10.0.14393.0 to < 10.0.14393.9612)
- Windows Server 2016 (10.0.14393.0 to < 10.0.14393.9612)
- Other Windows 10, Windows 11 and Windows Server releases are also listed in the official CVE record and the MSRC advisory.
Fixed in
- Windows 10 Version 1607 and Windows Server 2016: build 10.0.14393.9612 or later, October 2026 cumulative update KB5126868 (according to Rapid7; not yet confirmed on MSRC)
- Other affected versions: see the MSRC advisory
Workaround
Unknown. No vendor-published workaround was found.
Exploitation
- Not known to be exploited in the wild.
- CISA SSVC: Exploitation none, Automatable no, Technical Impact total.
- Not listed in the CISA KEV catalog.
- EPSS score 0.00273 (very low).
- No public proof of concept found in the sources reviewed.
Our recommendation
- Confirm the exact fixed build and KB number for your edition and architecture on the MSRC advisory.
- Install the October 2026 cumulative update on all Windows 10 1607 and Windows Server 2016 systems, then reboot.
- Identify which 1607 systems are still in use and plan an upgrade, because they will no longer receive security fixes after support ends.
- Limit local accounts on these hosts and monitor for public proof of concept or KEV addition.
Information from Microsoft (Patch Tuesday October 2026)
- Severity (Microsoft)
- Important
- Impact
- Security feature bypass – Windows PowerShell
- Status on Patch Tuesday
- Neither exploited nor publicly disclosed
- Exploitability assessment
- Exploitation less likely
- Product family
- Windows, Windows ESU (Extended Security Updates)
- Updates (KB)
- KB5127648, KB5126651, KB5126655, KB5126657, KB5126646, KB5126653
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide: CVE-2026-70185 msrc.microsoft.com
- Rapid7 vulnerability database: CVE-2026-70185 www.rapid7.com
- Vulners Microsoft CVE mirror: MS:CVE-2026-70185 vulners.com
- OpenCVE: CVE-2026-70185 app.opencve.io
- Vulmon: CVE-2026-70185 vulmon.com
- Vulners VulnRichment: CVE-2026-70185 vulners.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 31 Oct 2026, 18:54.
Original description (NVD)
Protection mechanism failure in Windows PowerShell allows an authorized attacker to bypass a security feature locally.
NVD references (1)
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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