CVE-2024-36956

What it actually does

thermal_debug_tz_remove() fails to free all memory allocated for thermal zone diagnostics, leaving allocations unreachable after the struct thermal_debugfs object is freed.

Why it matters to the business

Systems performing frequent thermal zone add/remove operations may experience gradual memory exhaustion, leading to degraded performance or crashes on long-running Linux servers and embedded devices.

How an attack unfolds

An attacker with local access repeatedly triggers thermal zone creation and removal (via sysfs or hardware events) to exhaust kernel memory without triggering any explicit exploit code.

How to fix it

Upgrade the Linux kernel to a version containing commit f51564e4b3992b53df79460ed5781a5330b5b1d5 or later stable releases; rebuild and reboot with the patched kernel.

How to confirm the fix worked

Confirm the running kernel contains commit f51564e4b3992b53df79460ed5781a5330b5b1d5 via git log or kernel version string; monitor kernel memory statistics for reduced leak rates after zone removal.

Typical attack path

1. Obtain local access to a Linux system running kernel 6.8 or later
2. Trigger repeated addition and removal of thermal zones through debugfs or thermal subsystem interfaces
3. Accumulate unreachable memory allocations until system resources are exhausted

How to detect it

Review kernel memory statistics and slab allocator usage over time for unexpected growth correlated with thermal zone removal events; examine dmesg or debugfs traces for repeated thermal zone lifecycle operations.

What your security team should do

• Prioritize kernel upgrade on all affected 6.8+ systems within standard maintenance windows
• Monitor resident memory usage on hosts with dynamic thermal zones
• Apply the fix in the next scheduled kernel update cycle if immediate patching is not feasible