WinFsp through 2.2.26215 contains a null pointer dereference vulnerability in the kernel driver's Fast I/O device control handler that fails to validate the volume context before use. An unprivileged local user can trigger a denial of service by opening the WinFsp control device and issuing FSP_IOCTL_TRANSACT requests, causing a system crash.

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Exploitation none

Automatable no

Technical Impact partial

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
winfsp winfsp unaffected
Version Status Constraints
0 affected ≤ 2.2.26215

No data.

No data.

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Vendors Products
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Winfsp Subscribe

Project Subscriptions

Vendors Products
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Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/winfsp/winfsp cve-icon cve-icon
https://github.com/winfsp/winfsp/blob/v2.2B4/src/sys/devctl.c#L105-L114 cve-icon cve-icon
https://github.com/winfsp/winfsp/blob/v2.2B4/src/sys/devctl.c#L146-L152 cve-icon cve-icon
https://github.com/winfsp/winfsp/blob/v2.2B4/src/sys/devctl.c#L68-L73 cve-icon cve-icon
https://github.com/winfsp/winfsp/blob/v2.2B4/src/sys/volume.c#L1059-L1060 cve-icon cve-icon
https://github.com/winfsp/winfsp/commit/b8103265ec63fa87ac264c62bb796dbc38376652 cve-icon cve-icon
https://github.com/winfsp/winfsp/releases/tag/v2.2B4 cve-icon cve-icon
https://www.vulncheck.com/advisories/winfsp-through-2.2.26215-null-pointer-dereference-via-fast-i-o cve-icon cve-icon
History

Fri, 18 Sep 2026 23:45:00 +0000

Type Values Removed Values Added
First Time appeared Winfsp
Winfsp winfsp
Vendors & Products Winfsp
Winfsp winfsp

Fri, 18 Sep 2026 21:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Fri, 18 Sep 2026 15:30:00 +0000

Type Values Removed Values Added
Description WinFsp through 2.2.26215 contains a null pointer dereference vulnerability in the kernel driver's Fast I/O device control handler that fails to validate the volume context before use. An unprivileged local user can trigger a denial of service by opening the WinFsp control device and issuing FSP_IOCTL_TRANSACT requests, causing a system crash.
Title WinFsp through 2.2.26215 NULL Pointer Dereference via Fast I/O
Weaknesses CWE-476
References
Metrics cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

cvssV4_0

{'score': 6.8, 'vector': 'CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-09-18T16:18:45.126Z

Reserved: 2026-09-18T14:39:01.816Z

Link: CVE-2026-93689

cve-icon Vulnrichment

Updated: 2026-09-18T16:18:40.276Z

cve-icon NVD

Status : Received

Published: 2026-09-18T16:17:15.837

Modified: 2026-09-18T17:17:07.437

Link: CVE-2026-93689

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-18T23:00:06Z

Weaknesses