CVE-2026-64233

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

usb: gadget: uvc: hold opts->lock across XU walks in uvc_function_bind

uvc_function_bind() walks &opts->extension_units twice without holding

opts->lock:

- directly, for the iExtension string-descriptor fixup loop;

- indirectly, four times via uvc_copy_descriptors() (once per speed),

where the helper iterates uvc->desc.extension_units (which aliases

&opts->extension_units) to size and emit XU descriptors.

The configfs side (uvcg_extension_make / uvcg_extension_drop, in

drivers/usb/gadget/function/uvc_configfs.c) takes opts->lock around its

list_add_tail / list_del operations. A privileged userspace process

that holds the configfs subtree open and writes the gadget UDC name

to bind the function while concurrently rmdir()'ing an extensions

subdir can race uvcg_extension_drop() against the bind-time list walks

and dereference a freed struct uvcg_extension.

Hold opts->lock from the start of the XU string-

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References