CVE-2026-93133

What it actually does

Uninitialized link_handle variable in riscv_acpi_add_prt_dep() when acpi_get_handle() fails, leading to use of invalid memory during ACPI PRT dependency processing on RISC-V systems.

Why it matters to the business

Potential kernel instability or crashes during boot or device enumeration on RISC-V platforms using ACPI, increasing downtime risk for affected hardware deployments.

How an attack unfolds

An attacker with local or boot-time control over ACPI tables on a vulnerable RISC-V system triggers the riscv_acpi_add_prt_dep path where acpi_get_handle fails, resulting in undefined behavior from the uninitialized handle.

How to fix it

Apply the upstream kernel patch that adds explicit status checking for acpi_get_handle and skips the entry on failure; rebuild and deploy updated kernel images for RISC-V systems.

How to confirm the fix worked

Inspect kernel source for the patched riscv_acpi_add_prt_dep function containing the status check; verify running kernel version contains the fix via kernel build configuration or changelog.

Typical attack path

1. Gain ability to influence ACPI tables or boot environment on RISC-V target
2. Trigger kernel ACPI initialization code path that calls riscv_acpi_add_prt_dep
3. Cause acpi_get_handle to return failure for the PRT entry
4. Induce use of uninitialized link_handle leading to kernel fault or corruption

How to detect it

Review kernel logs and crash dumps for ACPI-related faults during RISC-V initialization; correlate boot failures with absence of the status check in the affected function.

What your security team should do

• Prioritize kernel updates for all RISC-V Linux deployments using ACPI
• Monitor upstream stable kernel releases for inclusion of this fix
• Test ACPI-enabled RISC-V boot paths in staging environments before production rollout