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

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

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **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:** Yes
- **Published:** 14 Feb 2026
- **Updated:** 11 May 2026
- **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

## 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: Linux kernel.

## How do I fix CVE-2025-71200?

Apply the vendor's patch.

## Is CVE-2025-71200 being exploited?

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

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-71200 and fix it if it is affected.

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

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-71200/ (Markdown: https://insights.sbomify.com/CVE-2025-71200/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-71200
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-71200
- OSV: https://osv.dev/vulnerability/CVE-2025-71200

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-71200/
Summaries are generated and may contain mistakes; the official description above is the record.