SB20260727247 - Improper Initialization in Linux kernel gadget function driver

Description

This security bulletin contains information about 1 vulnerability.

1) Improper Initialization (CVE-ID: CVE-2026-64327)

CWE-ID: CWE-665 - Improper Initialization

CVSSv4: 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

The vulnerability allows a local user to cause a denial of service.

The vulnerability exists due to improper initialization in the f_fs functionfs endpoint file handling when processing early userspace ioctls before USB host connection. A local user can invoke FUNCTIONFS_DMABUF_ATTACH on an endpoint file before the host connects to cause a denial of service.

The issue occurs because endpoint direction checks can use an incorrect DMA direction before the endpoint files are fully initialized for connection state.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/82cf1142e5ccf2b6d6d22ef713aaf3e5f2b5716b
• https://git.kernel.org/stable/c/82cfd4739011bdc7e87b5d585703427e89ddfaa5
• https://git.kernel.org/stable/c/9e04055ab5fc0470a0031ee6934739f9aa8f34a5
• https://git.kernel.org/stable/c/f99f32ea9aa976afcbec20647ed33b50a52002c1