CVE-2021-47102: 
Linux Kernel vulnerability analysis and mitigation

CVE-2021-47102 affects the Linux kernel and involves an incorrect structure access in the Marvell Prestera network driver. The vulnerability was discovered and disclosed in March 2024. The issue occurs in the net/marvell/prestera component where improper access to the upper_dev field, which is only meant for specific events (e.g., NETDEV_CHANGEUPPER), causes invalid memory access for other events when the pointer is not of type netdev_notifier_changeupper_info (Kernel Patch).

The vulnerability is classified as an out-of-bounds read (CWE-125) with a CVSS v3.1 base score of 7.1 HIGH (Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H). The issue manifests as a stack-out-of-bounds error in the prestera_netdev_port_event.constprop.0 function, where improper access to the upper_dev field leads to invalid memory access when handling certain network device events (NVD).

The vulnerability can lead to unauthorized read access to kernel memory, potentially exposing sensitive information. The KASAN (Kernel Address Sanitizer) logs indicate that the issue can result in stack-out-of-bounds reads, which could compromise system security and potentially lead to system crashes (Kernel Patch).

The vulnerability requires local access with low privileges to exploit. The attack complexity is low, and no user interaction is required. The issue can be triggered during network device operations, particularly when handling device notifications (NVD).

The vulnerability has been fixed in the Linux kernel through a patch that properly handles the structure access by using container_of to safely access the upper_dev field only when appropriate. The fix involves modifying the prestera_netdev_port_event function to correctly handle the structure access based on event types (Kernel Patch).