CVE-2022-50411

In the Linux kernel, the following vulnerability has been resolved:

ACPICA: Fix error code path in acpi_ds_call_control_method()

A use-after-free in acpi_ps_parse_aml() after a failing invocaion of acpi_ds_call_control_method() is reported by KASAN [1] and code inspection reveals that next_walk_state pushed to the thread by acpi_ds_create_walk_state() is freed on errors, but it is not popped from the thread beforehand. Thus acpi_ds_get_current_walk_state() called by acpi_ps_parse_aml() subsequently returns it as the new walk state which is incorrect.

To address this, make acpi_ds_call_control_method() call acpi_ds_pop_walk_state() to pop next_walk_state from the thread before returning an error.

A use-after-free in ACPICA’s error path allowed a freed walk state to be returned again, leading to kernel crashes during AML parsing. Exploitation realistically requires control over ACPI tables (firmware/ACPI override by root or a malicious hypervisor), so the impact is primarily local/physical and results in denial of service.

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.