CVE-2026-64233 usb: gadget: uvc: hold opts->lock across XU walks in uvc_function_bind

What is CVE-2026-64233?

CVE-2026-64233 is a medium-severity vulnerability in Linux kernel, published on 24 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official 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-descriptor fixup through the last uvc_copy_descriptors() call, releasing on the descriptor-error path via a new error_unlock label that drops the lock before falling through to the existing error label. This matches the locking discipline of the configfs callbacks and removes the only remaining unsynchronised reader of the XU list during bind.

Reachability: only privileged processes that can mount configfs and write to gadget UDC files can trigger the race, so this is a correctness fix rather than a security boundary.

Which versions are affected by CVE-2026-64233?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-64233?

Apply the vendor's patch.

Is CVE-2026-64233 being exploited?

There is no known exploitation of CVE-2026-64233 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BELL-CVE-2026-64233, DEBIAN-CVE-2026-64233, GHSA-3j5c-rcjj-m4jc, ROOT-OS-UBUNTU-2204-CVE-2026-64233, UBUNTU-CVE-2026-64233.