Important CVSS 8.8 EPSS 0.01243 2020-04 archive

Executive Summary

A security feature bypass vulnerability exists when Windows fails to properly handle token relationships. An attacker who successfully exploited the vulnerability could allow an application with a certain integrity level to execute code at a different integrity level, leading to a sandbox escape. The update addresses the vulnerability by correcting how Windows handles token relationships

Overview

8.8
CVSS HIGH
Important
MS Severity
Not Exploited
MS Exploit Status
Less Likely
MS Exploit Likelihood
Category Security Feature Bypass
Released Apr 14 2020
Last Updated Apr 14 2020
Publicly Disclosed No
CISA KEV Not Listed
Known Exploits None Known
EPSS Score 0.01243 — 0.65351 percentile
NVD CVSS 8.8 HIGH — differs from MSRC

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C
ATTACK VECTOR
Local
ATTACK COMPLEXITY
Low
PRIVILEGES REQUIRED
Low
USER INTERACTION
None
SCOPE
Changed
CONFIDENTIALITY
Low
INTEGRITY
Low
AVAILABILITY
Low
EXPLOIT CODE MATURITY
Proof-of-Concept
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 5.7

EPSS Score

0.01243
probability of exploitation in the next 30 days
0.65351 percentile - updated 2026-06-21
View on FIRST.org

Affected Products

8 affected products
Product KB Article Severity Impact Restart Required
Windows 10 Version 1903 for 32-bit Systems 4549951 (Security Update) Important Security Feature Bypass Yes
Windows 10 Version 1903 for ARM64-based Systems 4549951 (Security Update) Important Security Feature Bypass Yes
Windows 10 Version 1903 for x64-based Systems 4549951 (Security Update) Important Security Feature Bypass Yes
Windows 10 Version 1909 for 32-bit Systems 4549951 (Security Update) Important Security Feature Bypass Yes
Windows 10 Version 1909 for ARM64-based Systems 4549951 (Security Update) Important Security Feature Bypass Yes
Windows 10 Version 1909 for x64-based Systems 4549951 (Security Update) Important Security Feature Bypass Yes
Windows Server, version 1903 (Server Core installation) 4549951 (Security Update) Important Security Feature Bypass Yes
Windows Server, version 1909 (Server Core installation) 4549951 (Security Update) Important Security Feature Bypass Yes

Patches

1 patch
Article Type Restart
4549951 Security Update Yes

Known Exploits

Acknowledgments