CVE-2024-43868

What it actually does

Missing word alignment on riscv_kernel_entry in purgatory causes unhandled exceptions to crash when the kernel is configured to handle alignment traps delegated from SBI.

Why it matters to the business

RISC-V systems using kexec may experience unexpected crashes during boot or exception handling, increasing downtime and requiring urgent kernel updates across fleets.

How an attack unfolds

An attacker with the ability to trigger unaligned memory access during early boot or kexec transition can cause the system to crash instead of recovering via the kernel handler; listed threat actors have targeted similar Linux kernel resource issues in espionage and financial campaigns.

How to fix it

Update to Linux kernel commit 10ffafb456f293976c42f700578ef740467cb569 or later; Android devices require SoCVersion 2020-12-05 or newer containing the aligned riscv_kernel_entry change.

How to confirm the fix worked

Verify the presence of the alignment directive on riscv_kernel_entry in the built purgatory binary and confirm the kernel boots without crashes under delegated unaligned exception handling.

Typical attack path

1. Identify RISC-V target with kexec and delegated unaligned access handling enabled
2. Trigger an unaligned memory access during purgatory execution
3. Force exception path that relies on word-aligned kernel entry
4. Cause kernel crash due to misaligned handler entry

How to detect it

Review kernel boot logs and kexec-related dmesg entries for unaligned access crashes or purgatory failures on RISC-V systems; correlate with threat actor campaigns targeting Linux kernel resource handling.

What your security team should do

• Prioritize patching all RISC-V Linux kernels to the listed fixed commit within the next maintenance window
• Audit kexec configurations on RISC-V devices for delegated alignment handling
• Monitor EPSS and threat actor activity for any increase in exploitation of similar kernel entry issues