CVE-2021-47098: 
Linux Kernel vulnerability analysis and mitigation

CVE-2021-47098 affects the Linux kernel's hardware monitoring (hwmon) subsystem, specifically the lm90 driver. The vulnerability was discovered when an attempt was made to set the hysteresis value to MAX_LONG while the critical temperature limit was negative, leading to potential integer overflow/underflow conditions in hysteresis calculations. This issue was addressed in a fix that was committed to the Linux kernel (Kernel Commit).

The vulnerability stems from incomplete protection against integer underflows in temperature calculations. While a previous commit (b50aa49638c7) had addressed several underflow situations when writing temperature limits, it missed the scenario involving hysteresis value settings. The fix implements clamp_val() to ensure the provided value can never overflow or underflow, specifically clamping values between -128000l and 255000l. The vulnerability has been assigned a CVSS v3 base score of 6.0, indicating moderate severity (Red Hat CVE).

The vulnerability could potentially lead to integer overflow or underflow conditions in the Linux kernel's hardware monitoring subsystem, specifically affecting temperature calculations in systems using the lm90 driver. This could result in incorrect temperature readings or improper thermal management (Red Hat CVE).

The vulnerability requires local access with high privileges to exploit. The attack complexity is rated as low, but privileged access is required, and no user interaction is needed for exploitation (Red Hat CVE).

The vulnerability has been fixed in the Linux kernel through a patch that implements proper value clamping in the lm90 driver. Users should update their systems to a version that includes the fix. The patch specifically modifies the drivers/hwmon/lm90.c file to use clamp_val() instead of max() for value validation (Kernel Commit).