CVE-2024-47661

What it actually does

Assignment of value 0xFFFF to a uint8_t field (ramping_boundary in dmub_rb_cmd) causes integer overflow due to truncation from uint32_t, reported as two Coverity INTEGER_OVERFLOW findings in the AMD display driver.

Why it matters to the business

Unpatched Linux kernels with AMD display hardware may experience display subsystem instability or memory corruption; the issue also affects container build tooling via moby/buildkit, increasing operational risk for organizations running affected kernels or build pipelines until upgrades are applied.

How an attack unfolds

An attacker with local access or the ability to influence display command buffer construction supplies input that triggers the oversized assignment to ramping_boundary; the resulting truncation produces out-of-bounds behavior that can be leveraged for kernel memory corruption or denial of service.

How to fix it

Update the Linux kernel to commit 30d1b783b6eeaf49d311a072c70d618d993d01ec or later; update moby/buildkit to version 0.12.5 or newer.

How to confirm the fix worked

Confirm kernel source contains the ramping_boundary type change to uint8_t with value 0xFF; verify buildkit version is 0.12.5+; run static analysis tools such as Coverity on the display driver code to ensure the integer overflow findings are resolved.

Typical attack path

1. Identify system running vulnerable Linux kernel with AMD display hardware or affected buildkit version
2. Obtain local code execution or ability to submit display-related commands
3. Trigger dmub_rb_cmd construction that assigns 0xFFFF to the uint8_t ramping_boundary field
4. Exploit resulting integer truncation for memory corruption or crash

How to detect it

Review kernel logs for AMD display driver crashes or warnings around dmub_rb_cmd handling; inspect buildkit build logs for anomalous display-related failures; search system audit logs for unexpected processes interacting with the display subsystem shortly before instability.

What your security team should do

• Prioritize kernel and buildkit upgrades on all AMD-display Linux systems and build hosts
• Apply updates before any scheduled maintenance windows given the presence of the issue in the stable tree
• Monitor upstream stable kernel releases for additional backports of the same fix