CVE-2026-98764

/// Technical description

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

usb: gadget: f_fs: Fix NULL pointer dereference in FUNCTIONFS_ENDPOINT_DESC

When user space sets up FunctionFS with only full-speed descriptors

(e.g., flags = FUNCTIONFS_HAS_FS_DESC) and the gadget operates at a

higher speed (such as USB_SPEED_HIGH or USB_SPEED_SUPER),

config_ep_by_speed() detects that the function lacks descriptors for

the current speed, logs a warning, and falls back to full-speed

descriptors. The endpoint is then successfully enabled via

usb_ep_enable(), and epfile->ep becomes valid.

However, when user space subsequently issues the FUNCTIONFS_ENDPOINT_DESC

ioctl to query the endpoint descriptor, ffs_epfile_ioctl() selects the

descriptor index solely based on gadget->speed:

switch (epfile->ffs->gadget->speed) {

case USB_SPEED_SUPER:

case USB_SPEED_SUPER_PLUS:

desc_idx = 2;

break;

case USB_SPEED_HIGH:

desc_idx = 1;

break;

default:

desc_idx = 0;

}

desc = epfile->ep->descs[desc_idx]

/// 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