CVE-2024-26927

What it actually does

Missing bounds checks on firmware-provided size fields in ASoC SOF allow head->full_size - head->header_size to underflow, enabling out-of-bounds memory access when processing untrusted firmware data.

Why it matters to the business

Local attackers on affected Linux systems can trigger crashes or arbitrary code execution in audio subsystems, risking data compromise or kernel-level control on servers and endpoints using SOF audio drivers.

How an attack unfolds

An attacker with local access supplies crafted firmware data containing size values that cause arithmetic underflow during header processing; the kernel then performs memory operations using the resulting invalid length, leading to corruption or code execution.

How to fix it

Upgrade the Linux kernel to the commit d133d67e7e724102d1e53009c4f88afaaf3e167c or later stable releases that include the added negative and upper-bound checks on firmware size fields.

How to confirm the fix worked

Confirm the patch is applied by inspecting the source for the added bounds checks on full_size and header_size; test by attempting to load firmware with deliberately invalid sizes and verifying rejection.

Typical attack path

1. Obtain local access on a target running an affected kernel
2. Prepare malicious firmware image with negative or oversized header values
3. Trigger firmware loading through ALSA/SOF interfaces
4. Exploit resulting underflow for memory corruption or privilege escalation

How to detect it

Review kernel logs for SOF firmware parsing warnings or crashes involving size calculations; examine audit logs around firmware load events for anomalous audio driver activity.

What your security team should do

• Prioritize kernel updates on all systems using SOF audio drivers
• Restrict unprivileged firmware loading where possible via kernel configuration
• Monitor for local privilege-escalation attempts targeting audio subsystems