CVE-2023-53057: 
Linux Kernel vulnerability analysis and mitigation

CVE-2023-53057 is a global-out-of-bounds vulnerability discovered in the Linux kernel's Bluetooth HCI (Host Controller Interface) subsystem. The vulnerability was published on May 2, 2025, and affects the Linux kernel's Bluetooth implementation (NVD, Debian Security).

The vulnerability occurs in the hci_init_stage_sync function where the code incorrectly handles variable-length arrays. Specifically, when looping through stage arrays, the function assumes stage[i] is valid as long as stage[i-1].func is valid. While hci_init0[] and le_init2[] arrays properly implement an invalid element at the end, amp_init1[] and amp_init2[] arrays lack this invalid element, causing the function to access memory beyond the valid range (NVD).

The vulnerability results in a global-out-of-bounds read of size 8 bytes, which can be triggered during Bluetooth device initialization. This can potentially lead to system crashes and denial of service conditions when Bluetooth functionality is used (NVD).

The vulnerability can be triggered during Bluetooth device initialization through the hci_dev_open_sync function. The issue manifests in the kernel's Bluetooth subsystem and requires local access to a system with Bluetooth capabilities (NVD).

The vulnerability has been fixed by adding empty elements ({}) at the end of amp_init1[] and amp_init2[] arrays. Multiple Linux distributions have released patched kernel versions, including Debian and Ubuntu. Users are advised to update their systems to the latest kernel version that includes these fixes (Debian Security).