CVE-2021-40449

High (7.8) in Microsoft Windows. In CISA KEV since 2021-11-17, with known ransomware use. EPSS 82% chance of exploitation in the next 30 days.

EPSS

82% chance of exploitation in the next 30 days; higher than 99% of CVEs (scores of 2026-10-31)

CISA KEV

listed 2021-11-17, due 2021-12-01, known ransomware use

CWE

CWE-416

Published

2021-10-13

Modified

2026-06-17

Record from

the NVD, synced 2026-10-19

Affected

• microsoft:windows_10_1507
• microsoft:windows_10_1607
• microsoft:windows_10_1809
• microsoft:windows_10_1909
• microsoft:windows_10_2004
• microsoft:windows_10_20h2
• microsoft:windows_10_21h1
• microsoft:windows_11
• microsoft:windows_11_21h2
• microsoft:windows_7
• microsoft:windows_8.1
• microsoft:windows_rt_8.1
• microsoft:windows_server_2004
• microsoft:windows_server_2008
• microsoft:windows_server_2012
• microsoft:windows_server_2016
• microsoft:windows_server_2019
• microsoft:windows_server_2022
• microsoft:windows_server_20h2

References

• http://packetstormsecurity.com/files/164926/Win32k-NtGdiResetDC-Use-After-Free-Local-Privilege-Escalation.html
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-40449
• http://packetstormsecurity.com/files/164926/Win32k-NtGdiResetDC-Use-After-Free-Local-Privilege-Escalation.html
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-40449
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-40449

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