CVE-2021-47441: 
Linux Kernel vulnerability analysis and mitigation

CVE-2021-47441 affects the Linux kernel's mlxsw thermal driver. The vulnerability allows cooling states to be set above the maximum cooling state supported by the driver, which results in out-of-bounds memory accesses when thermal state transition statistics are enabled (CONFIG_THERMAL_STATISTICS=y). This issue was discovered in 2021 and has been fixed in subsequent kernel versions (Kernel Git).

The vulnerability occurs when a user attempts to set cooling states above the maximum supported state (10) through the sysfs interface. When thermal state transition statistics are enabled, the transition table is accessed with an invalid index, leading to out-of-bounds memory access. The CVSS v3.1 base score is 7.3 (HIGH) with vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:H (CISA-ADP).

The vulnerability can lead to out-of-bounds memory accesses in the kernel, potentially resulting in system crashes, information leaks, or other security implications when thermal state transition statistics are enabled. The impact is particularly relevant for systems using the Mellanox mlxsw thermal driver (Kernel Git).

The vulnerability requires local access and can be triggered through the sysfs interface by setting cooling states above the maximum supported value. A proof-of-concept exists showing how to trigger the vulnerability by writing values greater than the maximum state (10) to /sys/class/thermal/thermal_zone2/cdev0/cur_state (Kernel Git).

The issue has been fixed by adding proper validation of cooling states and returning an error when the state to be set exceeds the maximum cooling state supported by the driver. The fix also includes removing dead code related to invalid cooling states interpretation. Users should update to patched kernel versions that include the fix (Kernel Git).