CVE-2025-71188

What it actually does

Reference leak during DMA mux route allocation in lpc18xx-dmamux driver allows device reference to be retained without preventing driver data from disappearing, enabling memory corruption or resource exhaustion.

Why it matters to the business

Systems running affected Linux kernel builds may experience instability, crashes, or denial of service when the DMA engine path is exercised, with low but non-zero risk of broader impact in virtualized or embedded environments.

How an attack unfolds

An attacker with local access triggers repeated DMA route allocation paths in the lpc18xx-dmamux driver to exhaust references or trigger use-after-free conditions after driver data is released, leading to kernel instability.

How to fix it

Upgrade linux-virt and linux-virt-doc to 6.12.30-r0 or later; apply kernel commit 3d396ebfb3049a2b5fac51d2c967db5114b685e8 in stable trees.

How to confirm the fix worked

Verify running kernel version matches or exceeds the listed fixed releases; inspect dmamux probe paths in source for explicit put_device calls after platform device lookup.

Typical attack path

1. Obtain local user access on an affected Linux system
2. Exercise DMA mux route allocation via legitimate or crafted workloads
3. Repeat allocation to accumulate unreleased device references
4. Trigger conditions that release driver data while references remain
5. Cause memory corruption or kernel panic

How to detect it

Review kernel logs for repeated dmamux allocation failures or device reference warnings; correlate with process activity using DMA engine on lpc18xx platforms.

What your security team should do

• Apply the listed kernel updates on all affected MinimOS and GIT-based Linux deployments
• Prioritize patching in environments with heavy DMA usage such as embedded or virtualized workloads
• Monitor EPSS trend for any increase despite current low score