CVE-2026-21510highunder attackCWE-693

CVE-2026-21510: high-severity vulnerability in Microsoft Windows 10 Version 1607

Windows Shell Security Feature Bypass Vulnerability

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83Vexday Risk Score

Prioritize patching. It under exploitation confirmed by CISA, has an official Brazilian government alert and has a public proof of concept.

ssvc Actcvss 8.8epss 61%
from disclosure to weapon88 days
Published on NVDFeb 10
1st PoC+88d
CISA KEVFeb 10
Official alert in Brazil

Brazil's federal government published an alert, recommendation or bulletin that cites this vulnerability.

Source: CTIR Gov (GSI) and CISC Gov.br, under the CC BY-ND 3.0 license.
Action required by CISAfederal deadline: 2026-03-03

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

In short

A flaw in Windows Shell's protection system allows attackers to bypass security features remotely. This means someone over the network could circumvent built-in Windows security controls without proper authorization.

Technical detail

CWE-693 protection mechanism failure in Windows Shell enables remote bypass of security features through network-accessible vectors. The vulnerability requires network access but no user interaction or elevated privileges as pre-conditions, resulting in security control circumvention with potential for privilege escalation or unauthorized system access.

Summary generated and translated by AI from the official description.

The full analysis of this CVE is available in Portuguese →

Protection mechanism failure in Windows Shell allows an unauthorized attacker to bypass a security feature over a network.
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
Affected products
Microsoft · Windows 10 Version 1607Microsoft · Windows 10 Version 1809Microsoft · Windows 10 Version 21H2Microsoft · Windows 10 Version 22H2Microsoft · Windows 11 version 22H3Microsoft · Windows 11 Version 23H2Microsoft · Windows 11 Version 24H2Microsoft · Windows 11 Version 25H2Microsoft · Windows 11 version 26H1Microsoft · Windows Server 2012Microsoft · Windows Server 2012 R2Microsoft · Windows Server 2012 R2 (Server Core installation)Microsoft · Windows Server 2012 (Server Core installation)Microsoft · Windows Server 2016Microsoft · Windows Server 2016 (Server Core installation)Microsoft · Windows Server 2019Microsoft · Windows Server 2019 (Server Core installation)Microsoft · Windows Server 2022Microsoft · Windows Server 2022, 23H2 Edition (Server Core installation)Microsoft · Windows Server 2025Microsoft · Windows Server 2025 (Server Core installation)
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