🛡️ CVE-2026-31412 on Debian — linux

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 check_shl_overflow() macro to safely perform the shift and catch any overflows.