ZeroHour

CVE-2026-32202

KEVmass

Spoofing Flaw in Windows Shell (CVE-2026-32202) Actively Exploited

CISA: Microsoft Windows Protection Mechanism Failure Vulnerability

CVSS 3.1
4.3 medium
EPSS
64%p99
Published
()
KEV added
AI analysis

A protection mechanism in the Windows Shell fails (CWE-693), allowing an unauthorized attacker to perform spoofing against the shell over a network. Per the CVSS vector, the attack is network-based, requires no privileges or special conditions, but does require the targeted user to interact with attacker-supplied content. The impact is limited to confidentiality: an attacker can misrepresent information presented through the Windows Shell, gaining a spoofing foothold rather than code execution, privilege escalation, or persistence. Any organization running the affected Windows 10, Windows 11, or Windows Server builds is exposed, which effectively means most Windows estates. Microsoft has confirmed active exploitation, CISA added the flaw to its Known Exploited Vulnerabilities catalog on 2026-04-28, and a fix shipped in Microsoft's April 2026 Patch Tuesday release.

What to do: Apply Microsoft's April 2026 security updates to all affected Windows 10, Windows 11, and Windows Server hosts as a priority; the flaw is on CISA's KEV catalog, so U.S. federal agencies must patch within BOD 22-01 timelines or apply vendor-recommended mitigations. Until patched, note that exploitation requires user interaction with spoofed shell content, so user awareness about verifying shell-rendered information is a partial mitigations. No public PoC is known, but confirmed in-the-wild exploitation warrants prioritizing user-facing and internet-reachable systems for patching.

Affected
microsoft Windows 101607
microsoft Windows 101809
microsoft Windows 1021H2
microsoft Windows 1022H2
microsoft Windows 1123H2
microsoft Windows 1124H2
microsoft Windows 1125H2
microsoft Windows 1126H1
microsoft Windows Server 20122012
microsoft Windows Server 20162016
microsoft Windows Server 20192019
microsoft Windows Server 20222022
Estimated exposure
mass~1 billion+ Windows devices (affected builds span all supported Windows 10 and Windows 11 desktops plus Windows Server 2012-2022) — The Windows install base is widely estimated at over 1 billion devices, and the affected version list covers essentially the entire currently supported Windows desktop and server lineup, so exposure is effectively the full Windows fleet…

Order-of-magnitude estimate by the model from install counts, market share and public scan data it knows; verify before quoting.

Description

Protection mechanism failure in Windows Shell allows an unauthorized attacker to perform spoofing over a network.

CISA Known Exploited Vulnerability
Affected
Microsoft Windows
Required action
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Due date
Ransomware use
Unknown
Vendors
microsoft
Products
windows 10 1607, windows 10 1809, windows 10 21h2, windows 10 22h2, windows 11 23h2, windows 11 24h2, windows 11 25h2, windows 11 26h1, windows server 2012, windows server 2016, windows server 2019, windows server 2022
Weakness
CWE-693
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

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