CVE-2026-93689

medium

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.

References

https://www.vulncheck.com/advisories/winfsp-through-2.2.26215-null-pointer-dereference-via-fast-i-o

https://github.com/winfsp/winfsp/releases/tag/v2.2B4

https://github.com/winfsp/winfsp/commit/b8103265ec63fa87ac264c62bb796dbc38376652

https://github.com/winfsp/winfsp/blob/v2.2B4/src/sys/volume.c#L1059-L1060

https://github.com/winfsp/winfsp/blob/v2.2B4/src/sys/devctl.c#L68-L73

https://github.com/winfsp/winfsp/blob/v2.2B4/src/sys/devctl.c#L146-L152

https://github.com/winfsp/winfsp/blob/v2.2B4/src/sys/devctl.c#L105-L114

https://github.com/winfsp/winfsp

Details

Source: Mitre, NVD

Published: 2026-09-18

Updated: 2026-09-18

Risk Information

CVSS v2

Base Score: 4.6

Vector: CVSS2#AV:L/AC:L/Au:S/C:N/I:N/A:C

Severity: Medium

CVSS v3

Base Score: 5.5

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

Severity: Medium

CVSS v4

Base 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

Severity: Medium

EPSS

EPSS: 0.00116