Improper Initialization in Linux kernel - CVE-2026-31721
Published: May 2, 2026
Vulnerability identifier: #VU128971
CSH Severity: Low
CVSS v4.0: 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/E:U/U:Clear
CVE-ID: CVE-2026-31721
CWE-ID: CWE-665
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: Linux Foundation
Affected software:
Linux kernel
Linux kernel
Detailed vulnerability description
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to improper initialization of wait queues in f_hid when re-binding the UDC while a previously opened /dev/hidg0 file descriptor remains registered with epoll. A local user can use the file descriptor in epoll operations across unbind and rebind events to cause a denial of service.
The issue is triggered when the same file descriptor is used with EPOLL_CTL_ADD before unbinding and with EPOLL_CTL_DEL after rebinding.
How to mitigate CVE-2026-31721
Install security update from vendor's repository.
Sources
- https://git.kernel.org/stable/c/13440c0db227c5db01da751ed966dde4cdd2ea18
- https://git.kernel.org/stable/c/26a879a41ed960b3fb4ec773ef2788c515c0e488
- https://git.kernel.org/stable/c/4e0a88254ad59f6c53a34bf5fa241884ec09e8b2
- https://git.kernel.org/stable/c/5d1bb391ceeebb28327703dd07af8c6324af298f
- https://git.kernel.org/stable/c/81aee4500055876883658b024b6fb61801afe134
- https://git.kernel.org/stable/c/8ec6a58586f195a88479edcdb0b8027c39f12d03
- https://git.kernel.org/stable/c/de93e0862169b5539e00c2b9980b93fd80c37c0d
- https://git.kernel.org/stable/c/f7d00ee1c8082c8a134340aaf16d71a27e29c362