CVE-2021-33771KEV · OVERDUE

Microsoft Windows Kernel Privilege Escalation Vulnerability

High · published July 14, 2021

Patch now

Confirmed exploited, and the score agrees

CVSS calls it high at 7.8. It is confirmed in active exploitation. It sits in the 95.7th percentile for exploit probability.

1803
days past CISA
deadline
CVSS v3.1
7.8
EPSS
10%
Percentile
95.7
In the wild
Confirmed
What it is

⚠️ A sneaky privilege escalation flaw in the Windows Kernel is open for business, and it’s been exploited in the wild! Think of this vulnerability like a faulty elevator in a high-rise building that lets anyone access restricted floors without a keycard — it undermines the very security the building relies on. 🎢 An attacker could leverage this exploit to gain elevated privileges, taking control of system operations and accessing sensitive areas they shouldn't touch. This means they could install malware, steal personal data, or even cripple the system entirely—yikes!

Put simply

Think of this vulnerability like a faulty elevator in a high-rise building that lets anyone access restricted floors without a keycard — it undermines the very security the building relies on. 🎢 This vulnerability exists due to improper validation of input in the Windows Kernel, allowing attackers to escalate their privileges and execute arbitrary code in the system context without proper authorization.

What to do

An attacker could leverage this exploit to gain elevated privileges, taking control of system operations and accessing sensitive areas they shouldn't touch. This means they could install malware, steal personal data, or even cripple the system entirely—yikes! Patch your systems immediately with the latest security updates from Microsoft to close this vulnerability. Regularly audit permissions and apply principle of least privilege to help minimize risks. 🛡️ You've got this! Patch up and keep your systems secure like the true security hero you are! 💪✨

The record
Technical detail
CVSS v3.1
7.8 · HIGH
Vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.10172 · 95.7th percentile
Published
2021-07-14T22:15Z
KEV added
2021-11-03 · due 2021-11-17
Affected products (14)
ProductVersionsFixed in
microsoft/windows_10_1507< 10.0.10240.1900310.0.10240.19003
microsoft/windows_10_1607< 10.0.14393.453010.0.14393.4530
microsoft/windows_10_1809< 10.0.17763.206110.0.17763.2061
microsoft/windows_10_1909< 10.0.18363.167910.0.18363.1679
microsoft/windows_10_2004< 10.0.19041.111010.0.19041.1110
microsoft/windows_10_20h2< 10.0.19042.111010.0.19042.1110
microsoft/windows_10_21h1< 10.0.19043.111010.0.19043.1110
microsoft/windows_8.1all versions—
microsoft/windows_rt_8.1all versions—
microsoft/windows_server_2004< 10.0.19041.111010.0.19041.1110
microsoft/windows_server_2012all versions—
microsoft/windows_server_2016< 10.0.14393.453010.0.14393.4530
microsoft/windows_server_2019< 10.0.17763.206110.0.17763.2061
microsoft/windows_server_20h2< 10.0.19042.111010.0.19042.1110
References (3)
EPSS history
Timeline
  • 03 NOV 00:00Z
    Added to CISA KEV — remediate by Nov 17
    kev
  • 14 JUL 17:53Z
    Windows Kernel Elevation of Privilege Vulnerability
    cvelistv5