# CVE-2025-38169: arm64/fpsimd: Avoid clobbering kernel FPSIMD state with SMSTOP

> A race condition in the Linux kernel ARM64 FPSIMD handling can corrupt kernel state, potentially leading to data modification or system crashes.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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:** 3 Jul 2025
- **Updated:** 15 Oct 2026
- **Also known as:** BELL-CVE-2025-38169, DEBIAN-CVE-2025-38169, GHSA-m2xh-87px-jgff, ROOT-OS-UBUNTU-2404-CVE-2025-38169, UBUNTU-CVE-2025-38169

## What is CVE-2025-38169?

CVE-2025-38169 is a high-severity memory corruption vulnerability in Linux kernel, published on 3 Jul 2025. 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:

arm64/fpsimd: Avoid clobbering kernel FPSIMD state with SMSTOP

On system with SME, a thread's kernel FPSIMD state may be erroneously
clobbered during a context switch immediately after that state is
restored. Systems without SME are unaffected.

If the CPU happens to be in streaming SVE mode before a context switch
to a thread with kernel FPSIMD state, fpsimd_thread_switch() will
restore the kernel FPSIMD state using fpsimd_load_kernel_state() while
the CPU is still in streaming SVE mode. When fpsimd_thread_switch()
subsequently calls fpsimd_flush_cpu_state(), this will execute an
SMSTOP, causing an exit from streaming SVE mode. The exit from
streaming SVE mode will cause the hardware to reset a number of
FPSIMD/SVE/SME registers, clobbering the FPSIMD state.

Fix this by calling fpsimd_flush_cpu_state() before restoring the kernel
FPSIMD state.

## Which versions are affected by CVE-2025-38169?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2025-38169?

Apply the vendor's patch.

## Is CVE-2025-38169 being exploited?

There is no known exploitation of CVE-2025-38169 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-2025-38169 and fix it if it is affected.

What it is: CVE-2025-38169 is a high-severity memory corruption vulnerability in Linux kernel, published on 3 Jul 2025. 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-2025-38169 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-2025-38169/ (Markdown: https://insights.sbomify.com/CVE-2025-38169/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-38169
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-38169
- OSV: https://osv.dev/vulnerability/CVE-2025-38169

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-38169/
Summaries are generated and may contain mistakes; the official description above is the record.