Important CVSS 5.3 EPSS 0.00871 2020-09 archive

Executive Summary

A security feature bypass vulnerability exists when a Windows Projected Filesystem improperly handles file redirections. An attacker who successfully exploited this vulnerability could delete a targeted file they would not have permissions to. To exploit this vulnerability, an attacker would first have to log on to the system. An attacker could then run a specially crafted application that could exploit the vulnerability. The security update addresses the vulnerability by correcting how Windows Projected Filesystem handle file redirections.

Overview

5.3
CVSS MEDIUM
Important
MS Severity
Not Exploited
MS Exploit Status
Less Likely
MS Exploit Likelihood
Category Security Feature Bypass
Released Sep 8 2020
Last Updated Sep 8 2020
Publicly Disclosed No
CISA KEV Not Listed
Known Exploits None Known
EPSS Score 0.00871 — 0.5408 percentile
NVD CVSS 5.3 MEDIUM — matches MSRC

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L/E:P/RL:O/RC:C
ATTACK VECTOR
Local
ATTACK COMPLEXITY
Low
PRIVILEGES REQUIRED
Low
USER INTERACTION
None
SCOPE
Unchanged
CONFIDENTIALITY
Low
INTEGRITY
Low
AVAILABILITY
Low
EXPLOIT CODE MATURITY
Proof-of-Concept
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 4.8

EPSS Score

0.00871
probability of exploitation in the next 30 days
0.5408 percentile - updated 2026-06-21
View on FIRST.org

Affected Products

4 affected products
Product KB Article Severity Impact Restart Required
Windows 10 Version 2004 for 32-bit Systems 4571756 (Security Update) Important Security Feature Bypass Yes
Windows 10 Version 2004 for ARM64-based Systems 4571756 (Security Update) Important Security Feature Bypass Yes
Windows 10 Version 2004 for x64-based Systems 4571756 (Security Update) Important Security Feature Bypass Yes
Windows Server, version 2004 (Server Core installation) 4571756 (Security Update) Important Security Feature Bypass Yes

Patches

1 patch
Article Type Restart
4571756 Security Update Yes

Known Exploits

Acknowledgments

Jonas Lykkegård, (@edwardzpeng), 0xfff