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CVE-2026-93689— WinFsp through 2.2.26215 NULL Pointer Dereference via Fast I/O

Quick assessment

Affected

winfsp winfsp

Exploitation

No confirmed in-the-wild exploitation; assess based on exposure

Recommended action

Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

WinFsp 版本 2.2.26215 及更早版本存在一个空指针解引用漏洞。该漏洞位于内核驱动的快速 I/O（Fast I/O）设备控制处理程序中，其在调用前未对卷上下文（volume context）进行有效验证。非特权本地用户可通过打开 WinFsp 控制设备并发出请求来触发此漏洞，从而导致系统崩溃，造成拒绝服务（DoS）。

CVSS 5.5 · Medium EPSS 0.15% · P5 Updated Sep 28, 2026

Possible ATT&CK Techniques 5 AI

T1202 · Indirect Command Execution T1063 T1305 T1499 · Endpoint Denial of Service T1499.001 · OS Exhaustion Flood

Affected Version Matrix 1

Vendor	Product	Version Range	Status
winfsp	winfsp	`≤ 2.2.26215`	affected

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Vulnerability Information

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Vulnerability Title

WinFsp through 2.2.26215 NULL Pointer Dereference via Fast I/O

Source: CVE Program / CVE List V5

Vulnerability 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.

Source: CVE Program / CVE List V5

CVSS Information

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Source: CVE Program / CVE List V5

Vulnerability Type

空指针解引用

Source: CVE Program / CVE List V5

Affected Products

Vendor	Product	Affected Versions	CPE	Subscribe
winfsp	winfsp	0 ~ 2.2.26215	-

II. Public POCs for CVE-2026-93689

#	POC Description	Source Link	Shenlong Link

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III. Intelligence Information for CVE-2026-93689

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Patches & Fixes for CVE-2026-93689 (1)

🔗 sys: FspFastIoDeviceControl: fix vulnerability reported by: Luigino C… · winfsp/winfsp@b810326 · GitHub Read full article patch

Other References for CVE-2026-93689 (6)

🔗 winfsp/src/sys/devctl.c at v2.2B4 · winfsp/winfsp · GitHub Read full article technical-description
🔗 winfsp/src/sys/devctl.c at v2.2B4 · winfsp/winfsp · GitHub Read full article technical-description
🔗 winfsp/src/sys/devctl.c at v2.2B4 · winfsp/winfsp · GitHub Read full article technical-description
🔗 GitHub - winfsp/winfsp: Windows File System Proxy - FUSE for Windows · GitHub Read full article product
🔗 Release WinFsp 2026 Beta4 · winfsp/winfsp · GitHub release-notes
🔗 WinFsp through 2.2.26215 NULL Pointer Dereference via Fast I/O | Advisories | VulnCheck third-party-advisory

https://www.cve.org/CVERecord?id=CVE-2026-93689

IV. Related Vulnerabilities

Same product: winfsp

Same vendor: winfsp

Same weakness: CWE-476