CVE-2021-40449
KEVRansomware UseMicrosoft Windows Win32k Privilege Escalation Vulnerability
Description
Unspecified vulnerability allows for an authenticated user to escalate privileges.
Win32k Elevation of Privilege Vulnerability
CVSS 3.1 vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HPublishedOct 13, 2021
Last modifiedJun 17, 2026
Added to KEVNov 17, 2021
Remediation dueDec 1, 2021
References
- packetstormsecurity.com/files/164926/Win32k-NtGdiResetDC-Use-After-Free-Local-Privilege-Escalation.htmlExploitThird Party Advisory
- portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-40449PatchVendor Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-40449US Government Resource
0 recent articles mention this CVE
87
Risk assessment · Critical
Actively exploited and used by ransomware crews. Patch immediately.
- Exploitation
- Confirmed in the wild (CISA KEV)
- Federal remediation deadline
- Overdue by 1790 days
- Ransomware
- Used in known ransomware campaigns
- CVSS
- 7.8 HIGH
- EPSS (30-day exploit probability)
- 81.9% · top 1% of all CVEs
- Weakness
- CWE-416
Recommended actions
- 1.Apply updates per vendor instructions.
- 2.Treat as emergency change: patch or isolate internet-facing instances first.
- 3.Hunt for compromise: review logs for the disclosure window, not just from the patch date.
- 4.Verify offline/immutable backups and segment the affected systems. This flaw is used for ransomware initial access.
Assessment is derived automatically from the live signals above; verify against your own asset inventory.