CVE-2023-36776: Win32k Elevation of Privilege Vulnerability

CVE-2023-36776 is an elevation of privilege vulnerability in Win32k, rated Important by Microsoft, with a CVSS 3.1 base score of 7 (High). An attacker can exploit it by an attacker with local access, with low privileges and without user interaction. Microsoft has not reported exploitation in the wild and rates exploitation as more likely. The EPSS model estimates a 2.05% probability of exploitation activity in the next 30 days, higher than 81% of all scored vulnerabilities. Microsoft released the fix on 10 October 2023 in the October 2023 Patch Tuesday, delivered through 15 security updates (KB5031361, KB5031364, KB5031358, KB5031356 and more). It affects 33 products in 2 product families (Windows, ESU).

Key facts

CVE ID: CVE-2023-36776
Severity: High CVSS 7
Microsoft severity: Important
Impact: Elevation of Privilege
Exploited in the wild: No
Publicly disclosed: No
Exploitation likelihood: More Likely
Weakness: CWE-416; CWE-362
EPSS: 2.05% (percentile 81%)
CISA KEV: Not listed
Released: 10 October 2023
Last updated: 10 October 2023
Patch Tuesday: October 2023 Patch Tuesday
Product families: Windows, ESU

CVSS score and vector

Microsoft scores CVE-2023-36776 at 7 (temporal 6.1) using CVSS 3.1. Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

Metric	Value
Attack vector	Local
Attack complexity	High
Privileges required	Low
User interaction	None
Scope	Unchanged
Confidentiality impact	High
Integrity impact	High
Availability impact	High
Exploit code maturity	Unproven
Remediation level	Official fix
Report confidence	Confirmed

Frequently asked questions (Microsoft)

What privileges could be gained by an attacker who successfully exploited the vulnerability?

A local, authenticated attacker could gain elevated local system or administrator privileges through a vulnerability in the Win32k.sys driver.

According to the CVSS metric, the attack complexity is high (AC:H). What does that mean for this vulnerability?

Successful exploitation of this vulnerability requires an attacker to win a race condition.

Affected products (33)

Windows

Product	Security update	Type	Fixed build	Restart
Windows 10 Version 1809 for 32-bit Systems	KB5031361	Security Update	10.0.17763.4974	Yes
Windows 10 Version 1809 for x64-based Systems	KB5031361	Security Update	10.0.17763.4974	Yes
Windows 10 Version 1809 for ARM64-based Systems	KB5031361	Security Update	10.0.17763.4974	Yes
Windows Server 2019	KB5031361	Security Update	10.0.17763.4974	Yes
Windows Server 2019 (Server Core installation)	KB5031361	Security Update	10.0.17763.4974	Yes
Windows Server 2022	KB5031364	Security Update	10.0.20348.2031	Yes
Windows Server 2022 (Server Core installation)	KB5031364	Security Update	10.0.20348.2031	Yes
Windows 11 version 21H2 for x64-based Systems	KB5031358	Security Update	10.0.22000.2538	Yes
Windows 11 version 21H2 for ARM64-based Systems	KB5031358	Security Update	10.0.22000.2538	Yes
Windows 10 Version 21H2 for 32-bit Systems	KB5031356	Security Update	10.0.19041.3570	Yes
Windows 10 Version 21H2 for ARM64-based Systems	KB5031356	Security Update	10.0.19041.3570	Yes
Windows 10 Version 21H2 for x64-based Systems	KB5031356	Security Update	10.0.19041.3570	Yes
Windows 11 Version 22H2 for ARM64-based Systems	KB5031354	Security Update	10.0.22621.2428	Yes
Windows 11 Version 22H2 for x64-based Systems	KB5031354	Security Update	10.0.22621.2428	Yes
Windows 10 Version 22H2 for x64-based Systems
Windows 10 Version 22H2 for ARM64-based Systems
Windows 10 Version 22H2 for 32-bit Systems
Windows 10 for 32-bit Systems	KB5031377	Security Update	10.0.10240.20232	Yes
Windows 10 for x64-based Systems	KB5031377	Security Update	10.0.10240.20232	Yes
Windows 10 Version 1607 for 32-bit Systems	KB5031362	Security Update	10.0.14393.6351	Yes
Windows 10 Version 1607 for x64-based Systems	KB5031362	Security Update	10.0.14393.6351	Yes
Windows Server 2016	KB5031362	Security Update	10.0.14393.6351	Yes
Windows Server 2016 (Server Core installation)	KB5031362	Security Update	10.0.14393.6351	Yes

ESU

Product	Security update	Type	Fixed build	Restart
Windows Server 2008 for 32-bit Systems Service Pack 2	KB5031416 KB5031411	Monthly Rollup Security Only	6.0.6003.22317 6.0.6003.22317	Yes Yes
Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation)	KB5031416 KB5031411	Monthly Rollup Security Only	6.0.6003.22317 6.0.6003.22317	Yes Yes
Windows Server 2008 for x64-based Systems Service Pack 2	KB5031416 KB5031411	Monthly Rollup Security Only	6.0.6003.22317 6.0.6003.22317	Yes Yes
Windows Server 2008 for x64-based Systems Service Pack 2 (Server Core installation)	KB5031416 KB5031411	Monthly Rollup Security Only	6.0.6003.22317 6.0.6003.22317	Yes Yes
Windows Server 2008 R2 for x64-based Systems Service Pack 1	KB5031408 KB5031441	Monthly Rollup Security Only	6.1.7601.26769 6.1.7601.26769	Yes Yes
Windows Server 2008 R2 for x64-based Systems Service Pack 1 (Server Core installation)	KB5031408 KB5031441	Monthly Rollup Security Only	6.1.7601.26769 6.1.7601.26769	Yes Yes
Windows Server 2012	KB5031442 KB5031427	Monthly Rollup Security Only	6.2.9200.24523 6.2.9200.24523	Yes Yes
Windows Server 2012 (Server Core installation)	KB5031442 KB5031427	Monthly Rollup Security Only	6.2.9200.24523 6.2.9200.24523	Yes Yes
Windows Server 2012 R2	KB5031419 KB5031407	Monthly Rollup Security Only	6.3.9600.21620 6.3.9600.21620	Yes Yes
Windows Server 2012 R2 (Server Core installation)	KB5031419 KB5031407	Monthly Rollup Security Only	6.3.9600.21620 6.3.9600.21620	Yes Yes

Security updates (15)

KB5031361 (Security Update)
KB5031364 (Security Update)
KB5031358 (Security Update)
KB5031356 (Security Update)
KB5031354 (Security Update)
KB5031377 (Security Update)
KB5031362 (Security Update)
KB5031416 (Monthly Rollup)
KB5031411 (Security Only)
KB5031408 (Monthly Rollup)
KB5031441 (Security Only)
KB5031442 (Monthly Rollup)
KB5031427 (Security Only)
KB5031419 (Monthly Rollup)
KB5031407 (Security Only)

NIST NVD data

NVD status: Modified
NVD CVSS: 7 (HIGH)
NVD weakness: CWE-416; CWE-362
Published to NVD: 10 October 2023
NVD last modified: 17 June 2026

Affected configurations (CPE)

Product	Vulnerable versions
windows 10 1507	before 10.0.10240.20232
windows 10 1607	before 10.0.14393.6351
windows 10 1809	before 10.0.17763.4974
windows 10 21h2	before 10.0.19041.3570
windows 10 22h2	before 10.0.19045.3570
windows 11 21h2	before 10.0.22000.2538
windows 11 22h2	before 10.0.22621.2428
windows server 2008	all listed versions
windows server 2008 r2 (x64)	all listed versions
windows server 2012	all listed versions
windows server 2012 r2	all listed versions
windows server 2016	all listed versions
windows server 2019	all listed versions
windows server 2022	all listed versions

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-36776 (Patch, Vendor Advisory)
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2023-36776 (Patch, Vendor Advisory)

Acknowledgments

jackery

Revision history

Version	Date	Description
1.0	10 October 2023	Information published.