CVE-2024-49911

What it actually does

Null pointer dereference in dcn20_set_output_transfer_func due to missing check on set_output_gamma function pointer before dereference, allowing potential kernel memory corruption on AMD display hardware.

Why it matters to the business

System instability or crashes on affected Linux systems using AMD graphics, resulting in operational downtime and requiring kernel updates across deployments with moderate ecosystem prevalence in stable kernel trees.

How an attack unfolds

An attacker with local access or ability to influence display driver state triggers the vulnerable code path by supplying conditions where set_output_gamma remains null, leading to dereference; listed threat actors associated with Linux kernel memory issues could leverage similar patterns in espionage or financially motivated campaigns though no confirmed exploitation exists for this flaw.

How to fix it

Apply kernel updates containing commit e8a24767899c86f4c5f1e4d3b2608942d054900f or libecap package 0:1.0.1-2.module+el8.4.0+404+316a0dc5; rebuild and deploy affected stable kernels from git repositories.

How to confirm the fix worked

Verify presence of null check for set_output_gamma prior to call at the previously vulnerable line; confirm updated kernel versions via uname or package manager and test display functionality under load.

Typical attack path

1. Obtain local execution or graphics context on target Linux system with AMD display driver
2. Craft input or state to reach dcn20_set_output_transfer_func with null set_output_gamma
3. Trigger dereference to induce kernel panic or memory corruption
4. Escalate to denial of service or attempt further exploitation of resulting instability

How to detect it

Review kernel logs for oops or panic entries referencing dcn20_set_output_transfer_func or set_output_gamma; correlate with AMD display initialization events in dmesg or journalctl.

• dcn20_set_output_transfer_func
• set_output_gamma

What your security team should do

• Prioritize kernel upgrades on all AMD display-enabled systems within standard patch windows given low EPSS
• Monitor for related Linux kernel memory issues reported by listed threat actors
• Audit custom display driver integrations for similar function pointer handling