CVE-2024-42106: 
Linux Kernel vulnerability analysis and mitigation

CVE-2024-42106 affects the Linux kernel's inet_diag subsystem. The vulnerability was discovered when KMSAN reported an uninitialized value access in the raw_lookup() function. The issue occurs in the inet_diag_get_exact_compat() function which converts inet_diag_req to inet_diag_req_v2 but leaves the pad field uninitialized. This field is used for the underlying protocol in raw sockets diagnostics, corresponding to the sdiag_raw_protocol field in struct inet_diag_req_raw (Kernel Patch).

The vulnerability stems from an uninitialized pad field in struct inet_diag_req_v2 when converting from inet_diag_req. The issue manifests when raw_lookup() attempts to access the sdiag_raw_protocol field, which corresponds to the uninitialized pad field. The vulnerability has been assigned a CVSS v3.1 Base Score of 5.5 (MEDIUM) with the vector string CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H (NVD).

The vulnerability can lead to a denial of service condition due to the use of uninitialized memory. The CVSS score indicates that while the vulnerability requires local access and low privileges, it can result in high availability impact to the affected system (NVD).

The vulnerability requires local access with low privileges to exploit. It was discovered through KMSAN (Kernel Memory Sanitizer) testing, which detected the uninitialized value access during system calls involving raw socket diagnostics (Kernel Patch).

The issue has been fixed by initializing the pad field in both inet_diag_get_exact_compat() and inet_diag_dump_compat() functions. The fix has been implemented in various Linux kernel versions including 4.10 through 4.19.318, 4.20 through 5.4.280, 5.5 through 5.10.222, and 5.11 through 5.15.163 (NVD).