CVE-2026-21510KEV · OVERDUECWE-693

Windows Shell Security Feature Bypass Vulnerability

High · published February 10, 2026

Patch now

Confirmed exploited, and the score agrees

CVSS calls it high at 8.8. It is confirmed in active exploitation. It sits in the 97.9th percentile for exploit probability.

235
days past CISA
deadline
CVSS v3.1
8.8
EPSS
25%
Percentile
97.9
In the wild
Confirmed
What it is

⚡ An unauthorized attacker can easily bypass security features in Windows Shell over a network – a backdoor so inviting, it’s practically holding the door open! 🚪 Think of Windows Shell like a restaurant where only certain guests can enter the kitchen. But if the restaurant forgets to check IDs at the door, anyone could waltz into the kitchen and mess with the recipe, potentially serving up a dish of chaos instead of security. With this flaw, an attacker gains unauthorized access, allowing them to manipulate system settings or data as if they were an authorized user. This could lead to data breaches, unauthorized changes, or even a full system compromise – absolutely devastating for any organization relying on network security!

Put simply

Think of Windows Shell like a restaurant where only certain guests can enter the kitchen. But if the restaurant forgets to check IDs at the door, anyone could waltz into the kitchen and mess with the recipe, potentially serving up a dish of chaos instead of security. This vulnerability arises from a failure in the protection mechanism of Windows Shell, enabling attackers to bypass essential security features without proper authorization.

What to do

With this flaw, an attacker gains unauthorized access, allowing them to manipulate system settings or data as if they were an authorized user. This could lead to data breaches, unauthorized changes, or even a full system compromise – absolutely devastating for any organization relying on network security! Immediate action is required: apply the latest security patches from Microsoft for Windows Shell. Additionally, review and enhance network security measures to limit unauthorized access. Regular audits can further help mitigate risks associated with this vulnerability. You’ve got this! By taking these steps, you’ll bolster your defenses and keep your systems secure. 🛡️

The record
Technical detail
CVSS v3.1
8.8 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C
CVSS v4.0
Not supplied
EPSS
0.24537 · 97.9th percentile
Weakness
CWE-693 · Protection Mechanism Failure
Published
2026-02-10T17:51Z
KEV added
2026-02-10 · due 2026-03-03
EPSS history
Timeline
  • 10 FEB 17:51Z
    Windows Shell Security Feature Bypass Vulnerability
    cvelistv5
  • 10 FEB 00:00Z
    Added to CISA KEV — remediate by Mar 3
    kev