CVE-2021-34484KEV · OVERDUE

Microsoft Windows User Profile Service Privilege Escalation Vulnerability

High · published August 12, 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 97.6th percentile for exploit probability.

1647
days past CISA
deadline
CVSS v3.1
7.8
EPSS
22%
Percentile
97.6
In the wild
Confirmed
What it is

⚡ An unauthorized user can elevate their privileges on Windows systems with just a few crafty moves! Think of it like a hotel receptionist who, without checking, gives out master keys to random guests — suddenly, anyone can access any room! 🏨 This vulnerability allows malicious users to gain elevated privileges, potentially giving them access to sensitive data, the ability to install software, or even control the system itself. With such power, they could wreak absolute havoc, like throwing a wild party in a hotel room without the owner's permission!

Put simply

Think of it like a hotel receptionist who, without checking, gives out master keys to random guests — suddenly, anyone can access any room! 🏨 The Windows User Profile Service flaw lets attackers exploit improper access control, leading to privilege escalation. Basically, it opens a door for non-admin users to take on the roles and responsibilities of an admin without the proper authorization.

What to do

This vulnerability allows malicious users to gain elevated privileges, potentially giving them access to sensitive data, the ability to install software, or even control the system itself. With such power, they could wreak absolute havoc, like throwing a wild party in a hotel room without the owner's permission! Update Windows to the latest version immediately to mitigate this vulnerability. Make sure to review user permissions and access controls to prevent unauthorized privilege escalation. Regular system audits can also help catch any unauthorized access. 🔒 You’ve got this! With the right patches and precautions, you can keep your systems secure and your users safe! 🛡️

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
0.21827 · 97.6th percentile
Published
2021-08-12T22:15Z
KEV added
2022-03-31 · due 2022-04-21
Affected products (18)
ProductVersionsFixed in
microsoft/windows_10_1507< 10.0.10240.1902210.0.10240.19022
microsoft/windows_10_1607< 10.0.14393.458310.0.14393.4583
microsoft/windows_10_1809< 10.0.17763.211410.0.17763.2114
microsoft/windows_10_1909< 10.0.18363.173410.0.18363.1734
microsoft/windows_10_2004< 10.0.19041.116510.0.19041.1165
microsoft/windows_10_20h2< 10.0.19042.116510.0.19042.1165
microsoft/windows_10_21h1< 10.0.19043.116510.0.19043.1165
microsoft/windows_7all versions—
microsoft/windows_8.1all versions—
microsoft/windows_rt_8.1all versions—
microsoft/windows_server_2004< 10.0.19041.116510.0.19041.1165
microsoft/windows_server_2008all versions—
microsoft/windows_server_2008all versions—
microsoft/windows_server_2012all versions—
microsoft/windows_server_2012all versions—
microsoft/windows_server_2016< 10.0.14393.458310.0.14393.4583
microsoft/windows_server_2019< 10.0.17763.211410.0.17763.2114
microsoft/windows_server_20h2< 10.0.19042.116510.0.19042.1165
References (3)
EPSS history
Timeline
  • 31 MAR 00:00Z
    Added to CISA KEV — remediate by Apr 21
    kev
  • 12 AUG 18:11Z
    Windows User Profile Service Elevation of Privilege Vulnerability
    cvelistv5