CVE-2026-93689Hinoki check available

Local system crash via unchecked volume context

Published Sep 18, 2026 · Updated Sep 18, 2026

NULL pointer dereference in WinFsp 2.2.26215 and earlier allows local users to crash Windows through the WinFsp control device. The FspFastIoDeviceControl handler accepts FSP_IOCTL_TRANSACT when FileObject->FsContext2 is null, then later code dereferences the missing volume context. The path requires an unprivileged local account and no user interaction, and successful exploitation interrupts the entire Windows host.

CVSS severity6.8
Medium
EPSS probability0.15%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

NULL pointer dereference in WinFsp 2.2.26215 and earlier allows local users to crash Windows through the WinFsp control device. The FspFastIoDeviceControl handler accepts FSP_IOCTL_TRANSACT when FileObject->FsContext2 is null, then later code dereferences the missing volume context. The path requires an unprivileged local account and no user interaction, and successful exploitation interrupts the entire Windows host.

The record

CVE
CVE-2026-93689
Published
Sep 18, 2026
Updated
Sep 18, 2026
Vendor
WinFsp
Product
WinFsp
Classifications
CWE-476, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 18, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=2.2.26215

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

WinFsp · WinFspversion=0 <=2.2.26215

Published CVSS scores

6.8VulnCheck CNACVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
5.5VulnCheck CNACVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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