CVE-2025-71200 mmc: sdhci-of-dwcmshc: Prevent illegal clock reduction in HS200/HS400 mode

Medium 5.5 Published 14 Feb 2026 Updated 11 May 2026

Local attackers with root access can crash the system by illegally reducing the MMC clock frequency via debugfs in HS200/HS400 modes.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Local or same network only
Victim action needed: Not needed
Fix: Available

What is CVE-2025-71200?

CVE-2025-71200 is a medium-severity denial of service vulnerability in Linux kernel, published on 14 Feb 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

In the Linux kernel, the following vulnerability has been resolved:

mmc: sdhci-of-dwcmshc: Prevent illegal clock reduction in HS200/HS400 mode

When operating in HS200 or HS400 timing modes, reducing the clock frequency below 52MHz will lead to link broken as the Rockchip DWC MSHC controller requires maintaining a minimum clock of 52MHz in these modes.

Add a check to prevent illegal clock reduction through debugfs:

root@debian:/# echo 50000000 > /sys/kernel/debug/mmc0/clock root@debian:/# [ 30.090146] mmc0: running CQE recovery mmc0: cqhci: Failed to halt mmc0: cqhci: spurious TCN for tag 0 WARNING: drivers/mmc/host/cqhci-core.c:797 at cqhci_irq+0x254/0x818, CPU#1: kworker/1:0H/24 Modules linked in: CPU: 1 UID: 0 PID: 24 Comm: kworker/1:0H Not tainted 6.19.0-rc1-00001-g09db0998649d-dirty #204 PREEMPT Hardware name: Rockchip RK3588 EVB1 V10 Board (DT) Workqueue: kblockd blk_mq_run_work_fn pstate: 604000c9 (nZCv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : cqhci_irq+0x254/0x818 lr : cqhci_irq+0x254/0x818 ...

Which versions are affected by CVE-2025-71200?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2025-71200?

Apply the vendor's patch.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2025-71200 being exploited?

There is no known exploitation of CVE-2025-71200 in the wild and no public exploit code.

All Linux kernel vulnerabilities

Sources

Also known as BELL-CVE-2025-71200, DEBIAN-CVE-2025-71200, GHSA-5ggv-7qrf-gvxf, ROOT-OS-UBUNTU-2404-CVE-2025-71200, UBUNTU-CVE-2025-71200.