CVE-2021-40449
Win32k Elevation of Privilege Vulnerability
- Published
- Updated
- Reserved
- Assigned by
- microsoft
Description
Win32k Elevation of Privilege Vulnerability
Exploited in the wild
CISA lists this vulnerability in its Known Exploited Vulnerabilities catalog as Microsoft Windows Win32k Privilege Escalation Vulnerability.
- Added
- 17 Nov 2021
- Fix due (US federal)
- 1 Dec 2021
- Used by ransomware
- Known
Apply updates per vendor instructions.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. CISA's SSVC rates its exploitation: it is being exploited.
Timeline
ID reserved
By microsoft
- 41 days later
· 41 days later
Published
- 35 days later
· 35 days later
Added to CISA KEV
Known exploited, also by ransomware
- 4 years later
· 4 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| microsoftCNA (assigner) | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C |
| NVDNVD · Analyzed | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 81.9% · top 0.3% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: active · Automatable: no · Technical impact: total
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.8.
Weakness
- Elevation of Privilege
- CWE-416 Use After Free (opens in a new tab)All about CWE-416 and its CVEs
Affected products
Microsoft · Windows 10 Version 1809
- affected 10.0.0 – < 10.0.17763.2237
Microsoft · Windows Server 2019
- affected 10.0.0 – < 10.0.17763.2237
Microsoft · Windows Server 2019 (Server Core installation)
- affected 10.0.0 – < 10.0.17763.2237
Microsoft · Windows 10 Version 1909
- affected 10.0.0 – < 10.0.18363.1854
Microsoft · Windows 10 Version 21H1
- affected 10.0.0 – < 10.0.19041.1288
Microsoft · Windows Server 2022
- affected 10.0.0 – < 10.0.20348.288
Microsoft · Windows 10 Version 2004
- affected 10.0.0 – < 10.0.19041.1288
Microsoft · Windows Server version 2004
- affected 10.0.0 – < 10.0.19041.1288
Microsoft · Windows 10 Version 20H2
- affected 10.0.0 – < 10.0.19041.1288
Microsoft · Windows Server version 20H2
- affected 10.0.0 – < 10.0.19042.1288
Microsoft · Windows 11 version 21H2
- affected 10.0.0 – < 10.0.22000.258
Microsoft · Windows 10 Version 1507
- affected 10.0.0 – < 10.0.10240.19086
Microsoft · Windows 10 Version 1607
- affected 10.0.0 – < 10.0.14393.4704
Microsoft · Windows Server 2016
- affected 10.0.0 – < 10.0.14393.4704
Microsoft · Windows Server 2016 (Server Core installation)
- affected 10.0.0 – < 10.0.14393.4704
- affected 6.1.0 – < 6.1.7601.25740
Microsoft · Windows 7 Service Pack 1
- affected 6.1.0 – < 6.1.7601.25740
- affected 6.3.0 – < 6.3.9600.20144
Microsoft · Windows Server 2008 Service Pack 2
- affected 6.0.0 – < 6.0.6003.21251
Microsoft · Windows Server 2008 Service Pack 2 (Server Core installation)
- affected 6.0.0 – < 6.0.6003.21251
Microsoft · Windows Server 2008 Service Pack 2
- affected 6.0.0 – < 6.0.6003.21251
Microsoft · Windows Server 2008 R2 Service Pack 1
- affected 6.1.0 – < 6.1.7601.25740
Microsoft · Windows Server 2008 R2 Service Pack 1 (Server Core installation)
- affected 6.0.0 – < 6.1.7601.25740
Microsoft · Windows Server 2012
- affected 6.2.0 – < 6.2.9200.23490
Microsoft · Windows Server 2012 (Server Core installation)
- affected 6.2.0 – < 6.2.9200.23490
Microsoft · Windows Server 2012 R2
- affected 6.3.0 – < 6.3.9600.20144
Microsoft · Windows Server 2012 R2 (Server Core installation)
- affected 6.3.0 – < 6.3.9600.20144
References (3)
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-40449 (opens in a new tab)x_refsource_MISCx_transferred
- http://packetstormsecurity.com/files/164926/Win32k-NtGdiResetDC-Use-After-Free-Local-Privilege-Escalation.html (opens in a new tab)x_refsource_MISCx_transferred
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-40449 (opens in a new tab)government-resource
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- CISA KEV catalog (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2021-40449)Record last updated .