OnlyPatch
Windows splwow64

CVE-2021-1648 — Microsoft splwow64 Elevation of Privilege Vulnerability

Important CVSS 7.8 EPSS 0.01229 📢 Publicly disclosed 2021-01 archive

Executive Summary

None

Overview

7.8
CVSS HIGH
Important
MS Severity
Not Exploited
MS Exploit Status
Less Likely
MS Exploit Likelihood
Category Elevation of Privilege
Released Jan 12 2021
Last Updated Jan 12 2021
Publicly Disclosed Yes
CISA KEV Not Listed
Known Exploits None Known
EPSS Score 0.01229 — 0.65768 percentile
NVD CVSS 7.8 HIGH — matches MSRC

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/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
Unchanged
CONFIDENTIALITY
High
INTEGRITY
High
AVAILABILITY
High
EXPLOIT CODE MATURITY
Proof-of-Concept
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 7.0

EPSS Score

0.01229
probability of exploitation in the next 30 days
0.65768 percentile - updated 2026-07-25
View on FIRST.org

Affected Products

26 affected products
Product KB Article Severity Impact Restart Required
Windows 10 for 32-bit Systems 4598231 (Security Update) Important Elevation of Privilege Yes
Windows 10 for x64-based Systems 4598231 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 1607 for 32-bit Systems 4598243 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 1607 for x64-based Systems 4598243 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 1803 for 32-bit Systems 4598245 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 1803 for ARM64-based Systems 4598245 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 1803 for x64-based Systems 4598245 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 1809 for 32-bit Systems 4598230 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 1809 for ARM64-based Systems 4598230 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 1809 for x64-based Systems 4598230 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 1909 for 32-bit Systems 4598229 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 1909 for ARM64-based Systems 4598229 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 1909 for x64-based Systems 4598229 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 2004 for 32-bit Systems 4598242 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 2004 for ARM64-based Systems 4598242 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 2004 for x64-based Systems 4598242 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 20H2 for 32-bit Systems 4598242 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 20H2 for ARM64-based Systems 4598242 (Security Update) Important Elevation of Privilege Yes
Windows 10 Version 20H2 for x64-based Systems 4598242 (Security Update) Important Elevation of Privilege Yes
Windows 8.1 for 32-bit systems 4598285 (Monthly Rollup) 4598275 (Security Only) 4598285 (Monthly Rollup) Important Elevation of Privilege 4592484 Base: 7.8 Temporal: 7.0 Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C Yes 4598285 4598275 4598285 Windows 8.1 for x64-based systems 4598285 (Monthly Rollup) 4598275 (Security Only) 4598285 (Monthly Rollup) Important Elevation of Privilege 4592484 Base: 7.8 Temporal: 7.0 Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C Yes 4598285 4598275 4598285 Windows RT 8.1 4598285 (Monthly Rollup) 4598285 (Monthly Rollup) Important Elevation of Privilege 4592484 Base: 7.8 Temporal: 7.0 Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C Yes 4598285 4598285 Windows Server 2012 4598278 (Monthly Rollup) 4598297 (Security Only) Important Elevation of Privilege 4592468 Base: 7.8 Temporal: 7.0 Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C Yes 4598278 4598297 Windows Server 2012 (Server Core installation) 4598278 (Monthly Rollup) 4598297 (Security Only) Important Elevation of Privilege 4592468 Base: 7.8 Temporal: 7.0 Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C Yes 4598278 4598297 Windows Server 2012 R2 4598285 (Monthly Rollup) 4598275 (Security Only) 4598285 (Monthly Rollup) Important Elevation of Privilege 4592484 Base: 7.8 Temporal: 7.0 Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C Yes 4598285 4598275 4598285 Windows Server 2012 R2 (Server Core installation) 4598285 (Monthly Rollup) 4598275 (Security Only) 4598285 (Monthly Rollup) Important Elevation of Privilege 4592484 Base: 7.8 Temporal: 7.0 Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:P/RL:O/RC:C Yes 4598285 4598275 4598285 Windows Server 2016 4598243 (Security Update) Important Elevation of Privilege Yes
Windows Server 2016 (Server Core installation) 4598243 (Security Update) Important Elevation of Privilege Yes
Windows Server 2019 4598230 (Security Update) Important Elevation of Privilege Yes
Windows Server 2019 (Server Core installation) 4598230 (Security Update) Important Elevation of Privilege Yes
Windows Server, version 1909 (Server Core installation) 4598229 (Security Update) Important Elevation of Privilege Yes
Windows Server, version 2004 (Server Core installation) 4598242 (Security Update) Important Elevation of Privilege Yes
Windows Server, version 20H2 (Server Core Installation) 4598242 (Security Update) Important Elevation of Privilege Yes

Patches

6 patches
Article Type Restart
4598231 Security Update Yes
4598243 Security Update Yes
4598245 Security Update Yes
4598230 Security Update Yes
4598229 Security Update Yes
4598242 Security Update Yes

Known Exploits

Acknowledgments

k0shl
Elliot Cao ( @iamelli0t
Maddie Stone of Google Project Zero

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