CVE-2024-50214

What it actually does

Unfreed allocation of a drm_display_mode object returned by drm_mode_duplicate inside drm_display_mode_from_cea_vic, causing a kernel memory leak when the HDMI connector helper is exercised and later unloaded.

Why it matters to the business

Repeated load/unload cycles of affected kernel modules can gradually exhaust system memory, leading to performance degradation or eventual denial of service on Linux systems that use the DRM HDMI connector code; the large number of downstream dependents increases the scope of exposure across distributions and embedded devices.

How an attack unfolds

An attacker with the ability to trigger repeated modprobe and rmmod operations on the drm_connector_test module (or equivalent paths that invoke drm_display_mode_from_cea_vic) causes the kernel to allocate but never release mode structures; listed threat actors have been observed targeting similar Linux kernel memory-management flaws in espionage and financially motivated campaigns, though this specific leak has not been observed in ransomware activity.

How to fix it

Upgrade the Linux kernel to commit df2b00685cd33cd85be8910c7d6d22c4ebbf18bb or later; for gdk-pixbuf on Ubuntu 14.04 LTS apply version 2.30.7-0ubuntu1.6 or newer; rebuild and redeploy any custom kernels or distributions that incorporated the vulnerable helper.

How to confirm the fix worked

After patching, run the drm_connector_test kunit suite and confirm with kmemleak or slabinfo that no unreferenced drm_display_mode objects remain after module unload; verify the fixed commit is present in /proc/version or via package manager.

Typical attack path

1. Obtain local or container access sufficient to load/unload kernel test modules
2. Repeatedly invoke modprobe drm_connector_test followed by rmmod drm_connector_test
3. Monitor slab memory growth until the leak triggers OOM or forces a reboot
4. Chain with other kernel primitives if further exploitation is desired

How to detect it

Inspect kernel logs and kmemleak reports for repeated allocations originating from drm_mode_duplicate called by drm_display_mode_from_cea_vic; correlate with modprobe/rmmod events of drm_connector_test or similar modules; threat-actor TTPs for Linux kernel memory issues can be used to prioritize log sources.

What your security team should do

• Apply the kernel and gdk-pixbuf updates within the next maintenance window given the 702 days since disclosure
• Audit systems for custom DRM connector test modules and restrict their use to non-production environments
• Add kernel memory-leak monitoring to existing observability pipelines
• Review downstream package dependencies to ensure the fix propagates to all affected distributions