CVE-2024-50201

What it actually does

The radeon DRM driver fails to include the encoder itself in its possible_clones bitmask, violating the validation added by commit 74d2aacbe840 and triggering warnings in drm_mode_config_validate during driver initialization.

Why it matters to the business

Systems using older Radeon graphics hardware may encounter repeated kernel warnings on boot or driver load, potentially complicating diagnostics and requiring kernel updates that carry normal reboot and testing overhead; low EPSS and no KEV status indicate limited operational urgency.

How an attack unfolds

An attacker with local access loads or triggers the radeon driver on affected kernels; the misconfigured bitmask is detected during mode-config validation, producing warnings that could be leveraged in broader Linux kernel exploitation campaigns by espionage or financially motivated actors listed in threat reporting.

How to fix it

Apply the upstream fix from commit df75c78bfeff99f9b4815c3e79e2b1b1e34fe264 or update to a kernel containing that change; for Ubuntu 16.04 LTS passenger packages, install version 5.0.22-1 or later.

How to confirm the fix worked

Boot with the patched kernel and confirm the absence of "Bogus possible_clones" warnings in dmesg or kernel logs during radeon initialization; verify encoder possible_clones bitmask now includes the encoder itself via DRM debug output if enabled.

Typical attack path

1. Obtain local execution context on a Linux system with radeon hardware
2. Trigger radeon driver initialization or DRM mode configuration
3. Observe or log the bogus possible_clones warning emitted by drm_mode_config_validate
4. Combine the information or warning state with other kernel primitives for further impact

How to detect it

Search kernel logs (dmesg, journalctl, /var/log/kern.log) for the exact warning text emitted by drm_mode_config_validate; correlate with radeon driver load events and any listed Linux kernel exploitation campaigns involving uninitialized resources or out-of-bounds accesses.

• Bogus possible_clones: [ENCODER:
• possible_clones=0x
• WARNING: CPU:.*at drivers/gpu/drm/drm_mode_config.c:615 drm_mode_config_validate
• drm/radeon: Fix encoder->possible_clones

What your security team should do

• Prioritize kernel package updates to the fixed versions listed for each distribution
• Monitor kernel logs for the specific bogus possible_clones warning string on Radeon systems
• Include the CVE in routine kernel patch cycles given its low EPSS and non-KEV status
• Test graphics functionality post-update on any remaining Radeon hardware