CVE-2024-56766 is a high-severity vulnerability in the Linux kernel's mtd rawnand driver. It involves a double free error in the atmel_pmecc_create_user() function caused by improper memory management of the 'user' pointer. The pointer was originally allocated with kzalloc() but changed to devm_kzalloc(), making an explicit kfree(user) call result in a double free.