Vulnerability · Published Sep 18, 2026 · Assigned by VulnCheck
CVE-2026-93689WinFsp through 2.2.26215 NULL Pointer Dereference via Fast I/O
Medium 5.5
In plain English
A medium-severity null pointer dereference in winfsp from winfsp. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 5% of all known vulnerabilities).
Severity (CVSS 3.1)5.5Medium
Exploit odds (30 days)0.2%top 95.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official 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.
Affected products (as reported)
Weakness: CWE-476 · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
References
- Patch Commit patch
- https://github.com/winfsp/winfsp product
- https://github.com/winfsp/winfsp/blob/v2.2B4/src/sys/devctl.c#L68-L73 technical-description
- https://github.com/winfsp/winfsp/blob/v2.2B4/src/sys/devctl.c#L105-L114 technical-description
- https://github.com/winfsp/winfsp/blob/v2.2B4/src/sys/devctl.c#L146-L152 technical-description
- https://github.com/winfsp/winfsp/blob/v2.2B4/src/sys/volume.c#L1059-L1060 technical-description
- winfsp v2.2B4 Release Notes release-notes
- VulnCheck Advisory: WinFsp through 2.2.26215 NULL Pointer Dereference via Fast I/O third-party-advisory