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CVE-2021-1663

20
FAUCET Score

CVE-2021-1663 is an information disclosure vulnerability in the Windows Projected File System (ProjFS) FS Filter Driver, affecting Microsoft Windows 10 and Windows Server 2016. With a CVSS score of 5.5 (Medium), this vulnerability requires local access and low privileges to exploit, potentially leading to high confidentiality impact without affecting integrity or availability. While it has a low EPSS score and is not listed in KEV or the Hot List, it received some community discussion and media coverage at the time of its disclosure. There is no public exploit code available in Metasploit, Nuclei, or ExploitDB, and it is not known to be actively exploited.

Impacted Technologies

VendorProductVersion(s)CPE
20h2CPE matchmatch criteria
cpe:2.3:o:microsoft:windows_10:20h2:*:*:*:*:*:*:*
2004CPE matchmatch criteria
cpe:2.3:o:microsoft:windows_10:2004:*:*:*:*:*:*:*
20h2CPE matchmatch criteria
cpe:2.3:o:microsoft:windows_server_2016:20h2:*:*:*:*:*:*:*
2004CPE matchmatch criteria
cpe:2.3:o:microsoft:windows_server_2016:2004:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

5.5MEDIUM

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
NONE
Exploitability Score
1.8
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.20%
Probability of exploitation in next 30 days
EPSS Percentile
65.0%
Percentile rank of EPSS score among Peer Group
As of 2026-07-25
Model: v2026.06.15
This CVE's current EPSS score of 0.0120 is in the 97th percentile among its peer group of 15,932 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.0 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.1 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (7)

microsoftpatch availablevia msrc
Product: Windows 10 Version 20H2 for 32-bit Systems
View patch
microsoftpatch availablevia msrc
Product: Windows 10 Version 20H2 for ARM64-based Systems
View patch
microsoftpatch availablevia msrc
Product: Windows Server, version 20H2 (Server Core Installation)
View patch
microsoftpatch availablevia msrc
Product: Windows 10 Version 2004 for 32-bit Systems
View patch
microsoftpatch availablevia msrc
Product: Windows 10 Version 2004 for ARM64-based Systems
View patch
microsoftpatch availablevia msrc
Product: Windows 10 Version 2004 for x64-based Systems
View patch
microsoftpatch availablevia msrc
Product: Windows Server, version 2004 (Server Core installation)
View patch

Vendor Advisories (1)

microsoft2021-Jan/CVE-2021-1663Important

Windows Projected File System FS Filter Driver Information Disclosure Vulnerability

Jan 12, 2021

References

portal.msrc.microsoft.com / en-US/security-guidance/advisory/CVE-2021-1663
msrc.microsoft.com / update-guide/vulnerability/CVE-2021-1663