CVE-2026-50381: Composite Image File System driver (cimfs.sys) Information Disclosure Vulnerability

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-14 · updated 2026-10-28
Weakness: CWE-843

Description

Access of resource using incompatible type ('type confusion') in Composite Image File System Driver allows an authorized attacker to disclose information locally.

Affected products

Microsoft Windows 10: before 10.0.19044.7548 — fixed in 10.0.19044.7548
Microsoft Windows 10: before 10.0.19045.7548 — fixed in 10.0.19045.7548
Microsoft Windows 11: before 10.0.26100.8875 — fixed in 10.0.26100.8875
Microsoft Windows 11 25H2: before 10.0.26200.8875 — fixed in 10.0.26200.8875
Microsoft Windows 11 version 26H1: before 10.0.28000.2269; before 10.0.28000.2525 — fixed in 10.0.28000.2269, 10.0.28000.2525
Microsoft Windows Server 2022: before 10.0.20348.5386 — fixed in 10.0.20348.5386
Microsoft Windows Server 2025: before 10.0.26100.33158 — fixed in 10.0.26100.33158
Microsoft Windows 10: from 10.0.19044.0 before 10.0.19044.7548 — fixed in 10.0.19044.7548
Microsoft Windows 10: from 10.0.19045.0 before 10.0.19045.7548 — fixed in 10.0.19045.7548
Microsoft Windows 11: from 10.0.26100.0 before 10.0.26100.8875 — fixed in 10.0.26100.8875
Microsoft Windows 11 25H2: from 10.0.26200.0 before 10.0.26200.8875 — fixed in 10.0.26200.8875
Microsoft Windows 11 version 26H1: from 10.0.28000.0 before 10.0.28000.2525 — fixed in 10.0.28000.2525
Microsoft Windows Server 2022: from 10.0.20348.0 before 10.0.20348.5386 — fixed in 10.0.20348.5386
Microsoft Windows Server 2025: from 10.0.26100.0 before 10.0.26100.33158 — fixed in 10.0.26100.33158

How to fix

Upgrade to a fixed version: Microsoft Windows 10 10.0.19044.7548; Microsoft Windows 10 10.0.19045.7548; Microsoft Windows 11 10.0.26100.8875; Microsoft Windows 11 25H2 10.0.26200.8875; Microsoft Windows 11 version 26H1 10.0.28000.2269, 10.0.28000.2525; Microsoft Windows Server 2022 10.0.20348.5386; Microsoft Windows Server 2025 10.0.26100.33158; Microsoft Windows 10 10.0.19044.7548; Microsoft Windows 10 10.0.19045.7548; Microsoft Windows 11 10.0.26100.8875; Microsoft Windows 11 25H2 10.0.26200.8875; Microsoft Windows 11 version 26H1 10.0.28000.2525. Check the vendor advisory for mitigations.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-50381

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