CVE-2024-43830

What it actually does

Race condition during LED trigger deactivation allows sysfs attribute read/write handlers to execute after trigger-data has been freed by deactivate(), producing a use-after-free.

Why it matters to the business

Local attackers can crash Linux systems or escalate privileges to kernel level, leading to denial of service, data compromise, or full host takeover on any device running the affected kernel.

How an attack unfolds

An attacker with local access activates a trigger that registers custom sysfs groups, then forces concurrent deactivation while issuing sysfs operations so that the handlers dereference the now-freed trigger-data.

How to fix it

Upgrade the Linux kernel to a version containing the commit that moves device_remove_groups() before the deactivate() call; apply the fix as soon as vendor packages are available.

How to confirm the fix worked

Confirm the kernel source contains the corrected deactivation ordering (device_remove_groups before deactivate) and that the running kernel matches a patched build; recompile or reinstall if source-level verification is required.

Typical attack path

1. Obtain local user access on the target Linux system
2. Load or configure an LED trigger that allocates trigger-specific data in activate()
3. Trigger deactivation (e.g., via LED class device removal or trigger change) while issuing parallel sysfs attribute accesses
4. Leverage the resulting use-after-free for memory corruption, privilege escalation, or kernel panic

How to detect it

Inspect kernel logs (dmesg, /var/log/kern.log) for use-after-free warnings or oopses referencing LED trigger sysfs paths; correlate with process activity that manipulates /sys/class/leds entries around trigger deactivation events.

What your security team should do

• Prioritize kernel updates on all Linux hosts within the next patching cycle
• Restrict untrusted local accounts and limit LED trigger manipulation via SELinux/AppArmor where feasible
• Enable kernel hardening features such as KASAN or hardened usercopy to reduce exploitability
• Monitor internal vulnerability disclosure lists for downstream distributions shipping the fix