CVE-2026-31412

/// Technical description

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

usb: gadget: f_mass_storage: Fix potential integer overflow in check_command_size_in_blocks()

The `check_command_size_in_blocks()` function calculates the data size

in bytes by left shifting `common->data_size_from_cmnd` by the block

size (`common->curlun->blkbits`). However, it does not validate whether

this shift operation will cause an integer overflow.

Initially, the block size is set up in `fsg_lun_open()` , and the

`common->data_size_from_cmnd` is set up in `do_scsi_command()`. During

initialization, there is no integer overflow check for the interaction

between two variables.

So if a malicious USB host sends a SCSI READ or WRITE command

requesting a large amount of data (`common->data_size_from_cmnd`), the

left shift operation can wrap around. This results in a truncated data

size, which can bypass boundary checks and potentially lead to memory

corruption or out-of-bounds accesses.

Fix this by using the che

/// 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