CVE-2021-47368: 
Linux Kernel vulnerability analysis and mitigation

CVE-2021-47368 affects the Linux kernel's ENETC ethernet driver. The vulnerability was discovered in September 2021 and involves illegal memory access when reading affinity_hint. The issue occurs because irq_set_affinity_hit() stores a reference to a cpumask_t parameter in the irq descriptor that can be accessed later from irq_affinity_hint_proc_show(), but the parameter has only temporary stack memory storage (Kernel Commit).

The vulnerability stems from a memory management issue where the cpu_mask parameter passed to irq_set_affinity_hit() is allocated on the stack memory, making later accesses to it illegal. When the corresponding procfs affinity_hint file is read, this can result in paging request oops. The CVSS 3.1 base score is 8.1 HIGH with vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H (NVD).

The vulnerability can lead to illegal memory access and potential system crashes when reading the affinity_hint file, affecting system stability and potentially exposing sensitive information through memory access violations (Kernel Commit).

The issue has been fixed by using the get_cpu_mask() helper function, which provides permanent storage for the cpumask_t parameter instead of using stack memory. The fix was implemented in the Linux kernel through commit 7237a494decfa17d0b9d0076e6cee3235719de90 (Kernel Commit).