Microsoft PowerShell Security Feature Bypass Vulnerability

What kind of security feature could be bypassed by successfully exploiting this vulnerability?
An attacker who successfully exploited this vulnerability could bypass Windows Defender Application Control and PowerShell Constrained Language Mode restrictions, allowing untrusted code to run with capabilities those protections are designed to block.

How could an attacker exploit this vulnerability?
An authorized attacker who can execute Windows PowerShell locally under Constrained Language Mode could define and invoke a crafted workflow. Attacker-controlled workflow-definition data is inserted into a generated wrapper that runs in Full Language Mode, allowing the attacker to bypass Windows Defender Application Control and PowerShell Constrained Language Mode restrictions.

Security updates
10.0.14393.9688 — https://support.microsoft.com/help/5131291
10.0.17763.9487 — https://support.microsoft.com/help/5131085
10.0.19044.7846 — https://support.microsoft.com/help/5131096
10.0.20348.5870 — https://support.microsoft.com/help/5131090
10.0.22631.7711 — https://support.microsoft.com/help/5131087
10.0.26100.9968 — https://support.microsoft.com/help/5135385
10.0.26100.33812 — https://support.microsoft.com/help/5135386
10.0.28000.3501 — https://support.microsoft.com/help/5132059