CVE-2024-46814

What it actually does

Missing validation of HDCP_MESSAGE_ID_INVALID (-1) msg_id value before use as array index allows out-of-bounds memory access and buffer overruns in the AMD display driver.

Why it matters to the business

Potential kernel memory corruption on systems with AMD GPUs could lead to crashes, denial of service, or local privilege escalation; low exploitation likelihood but high impact on affected Linux distributions and containers.

How an attack unfolds

An attacker with local access crafts a malicious HDCP message with invalid msg_id to trigger the unchecked array access during transaction processing in the display driver, resulting in memory corruption that may be leveraged for code execution or system instability.

How to fix it

Update the Linux kernel to commit 916083054670060023d3f8a8ace895d710e268f4 or later; for runc update to 1.0.0-rc9.0.20200122160610-2fc03cc11c77 or newer; rebuild and reboot affected systems.

How to confirm the fix worked

Verify kernel source contains the msg_id bounds check before array indexing; confirm running kernel version includes the referenced commit; test HDCP functionality on AMD hardware post-update.

Typical attack path

1. Obtain local access on a vulnerable Linux system with AMD display hardware
2. Trigger HDCP message processing path with crafted invalid msg_id value
3. Exploit resulting buffer overrun for memory corruption
4. Escalate privileges or cause denial of service

How to detect it

Review kernel logs for AMD display driver crashes or oops messages around HDCP processing; look for unusual local process activity triggering display transactions; no public exploitation artifacts known.

What your security team should do

• Prioritize patching kernel packages on all AMD GPU systems within standard maintenance windows
• Monitor EPSS and threat intelligence for any rise in exploitation activity
• Restrict unprivileged local access where feasible until patches are applied