In the Linux kernel, the following vulnerability has been resolved: cpufreq: pcc: fix use-after-free and double free in _OSC evaluation pcc_cpufreq_do_osc() calls acpi_evaluate_object() twice for the two-phase _OSC negotiation. Between the two calls it freed output.pointer but left output.length unchanged. Since acpi_evaluate_object() treats a non-zero length with a non-NULL pointer as an existing buffer to write into, the second call wrote into freed memory (use-after-free). The subsequent kfree(output.pointer) at out_free then freed the same pointer a second time (double free). Reset output.pointer to NULL and output.length to ACPI_ALLOCATE_BUFFER after freeing the first result, so ACPICA allocates a fresh buffer for each phase independently.

A flaw was found in the Linux kernel's cpufreq subsystem. This vulnerability, a use-after-free and double-free error, occurs during the two-phase _OSC negotiation in the `pcc_cpufreq_do_osc()` function. A local attacker could exploit this memory corruption to cause a denial of service (DoS) or potentially achieve privilege escalation.

In the Linux kernel, the following vulnerability has been resolved: cpufreq: pcc: fix use-after-free and double free in _OSC evaluation pcc_cpufreq_do_osc() calls acpi_evaluate_object() twice for the two-phase _OSC negotiation. Between the two calls it freed output.pointer but left output.length unchanged. Since acpi_evaluate_object() treats a non-zero length with a non-NULL pointer as an existing buffer to write into, the second call wrote into freed memory (use-after-free). The subsequent kfree(output.pointer) at out_free then freed the same pointer a second time (double free). Reset output.pointer to NULL and output.length to ACPI_ALLOCATE_BUFFER after freeing the first result, so ACPICA allocates a fresh buffer for each phase independently.

cpufreq: pcc: fix use-after-free and double free in _OSC evaluation

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

In the Linux kernel, the following vulnerability has been resolved: cpufreq: pcc: fix use-after-free and double free in _OSC evaluation pcc_cpufreq_do_osc() calls acpi_evaluate_object() twice for the two-phase _OSC negotiation. Between the two calls it freed output.pointer but left output.length unchanged. Since acpi_evaluate_object() treats a non-zero length with a non-NULL pointer as an existing buffer to write into, the second call wrote into freed memory (use-after-free). The subsequent kfree(output.pointer) at out_free then freed the same pointer a second time (double free). Reset output.pointer to NULL and output.length to ACPI_ALLOCATE_BUFFER after freeing the first result, so ACPICA allocates a fresh buffer for each phase independently.