Exploited vulnerability · CISA KEV
Is CVE-2021-40450 exploited? Yes: in CISA KEV since 25 Apr 2022
Gociux · Microsoft Win32k · data: CISA KEV, CVE record, FIRST EPSS
Yes. CVE-2021-40450, Microsoft Win32k Privilege Escalation Vulnerability, is being exploited in the wild. CISA added it to its Known Exploited Vulnerabilities catalog on 25 Apr 2022, 194 days after it was published. It affects Microsoft Win32k. If you run it, CISA's required action is: Apply updates per vendor instructions.
exploitedYesCISA KEV · 25 Apr 2022
ransomwareNot knownno confirmed use
EPSSbelow top 10%lower predicted activity right now (it is still confirmed exploited)
severity7.8CVSS 3.1 · high
US federal due16 May 2022BOD 22-01 deadline
What it is
Microsoft Win32k contains an unspecified vulnerability that allows for privilege escalation.
| Vendor | Microsoft (391 exploited CVEs in KEV) |
| Product | Win32k |
| Vulnerability | Microsoft Win32k Privilege Escalation Vulnerability |
| Weakness | not specified |
| Published | 13 Oct 2021 |
| Added to KEV | 25 Apr 2022 |
| Reported by (CNA) | microsoft |
What to do
- Check whether you run it. Look for Win32k in your asset inventory, including appliances and cloud images. Stack check lists every exploited Microsoft CVE at once.
- Apply the fix. Apply updates per vendor instructions.
- If you can't patch today, take the affected service off the internet or restrict who can reach it, and check its logs for signs of compromise since 13 Oct 2021.
- Get told next time. Email alerts when CISA adds a CVE for Microsoft.
Other exploited CVEs in Win32k
- CVE-2016-0165: Microsoft Win32k Privilege Escalation Vulnerability (22 Jun 2023)
- CVE-2023-29336: Microsoft Win32K Privilege Escalation Vulnerability (9 May 2023)
- CVE-2015-2360: Microsoft Win32k Privilege Escalation Vulnerability (25 May 2022)
- CVE-2018-8589: Microsoft Win32k Privilege Escalation Vulnerability (23 May 2022)
- CVE-2014-4113: Microsoft Win32k Privilege Escalation Vulnerability (4 May 2022)
- CVE-2021-41357: Microsoft Win32k Privilege Escalation Vulnerability (25 Apr 2022)
References
Questions
Is CVE-2021-40450 being exploited?
Yes. CISA added CVE-2021-40450 to the Known Exploited Vulnerabilities catalog on 25 Apr 2022, which means there is reliable evidence of exploitation in the wild.
Is CVE-2021-40450 used in ransomware attacks?
CISA does not list known ransomware use for it. That can change, and exploitation alone is reason to fix it first.
How do I fix CVE-2021-40450?
Apply updates per vendor instructions. Check Microsoft's advisory for the fixed versions, and if you can't patch quickly, restrict access to the affected Win32k and watch it for signs of compromise.
Sources: CISA KEV (exploitation, ransomware use, required action, due date), the CVE record (publication date, CVSS, CNA), NVD and FIRST EPSS (live score). More: all KEV additions in April 2022 · Microsoft scorecard · act-now radar.
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