CVE-2024-57877: 
Linux Kernel vulnerability analysis and mitigation

CVE-2024-57877 is a vulnerability in the Linux kernel's ARM64 ptrace implementation, specifically in the handling of SETREGSET for NTARMPOE. The issue was discovered and disclosed on January 11, 2025, affecting Linux kernel versions from 6.12 up to (excluding) 6.12.5. The vulnerability stems from an uninitialized temporary 'ctrl' variable in the poe_set() function, which could lead to information disclosure (NVD).

The vulnerability occurs when a SETREGSET call with a length of zero is made, leaving the temporary 'ctrl' variable uninitialized. This results in an arbitrary value being written back to target->thread.por_el0, potentially exposing up to 64 bits of memory from the kernel stack. The read is confined to a specific stack slot, and the vulnerability does not provide write capabilities. The issue has been assigned a CVSS v3.1 base score of 6.1 (MEDIUM) with the vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H (NVD).

The vulnerability can lead to the disclosure of kernel stack memory, potentially exposing sensitive information. The impact is limited to reading up to 64 bits of memory from a specific slot on the kernel stack. The vulnerability does not provide any write mechanism, limiting its potential for exploitation (NVD).

The vulnerability has been fixed by initializing the temporary value before copying the regset from userspace, similar to other regsets (e.g., NTPRSTATUS, NTPRFPREG, NTARMSYSTEMCALL). The fix ensures that in the case of a zero-length write, the existing contents of POREL1 will be retained. The patch is available in Linux kernel version 6.12.5 and later (Kernel Patch).