---
id: CVE-2025-38169
title: |-
  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 …
summary: |-
  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 …
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-368
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 6.8.12, < 6.9'
  - 'linux_kernel >= 6.9.3, < 6.12.34'
  - 'linux_kernel >= 6.13, < 6.15.3'
patched:
  - linux_kernel 6.15.3
published: '2025-07-03'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T22:18:32.380'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-38169'
references:
  - url: 'https://git.kernel.org/stable/c/01098d893fa8a6edb2b56e178b798e3e6b674f02'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/55d52af498daea75aa03ba9b7e444c8ae495ac20'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a305821f597ec943849d3e53924adb88c61ed682'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-38169.json
  - url: 'https://access.redhat.com/security/cve/CVE-2025-38169'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2376067'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2025-38169'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2025-38169'
  - url: >-
      https://lore.kernel.org/linux-cve-announce/2025070342-CVE-2025-38169-11b6@gregkh/T
tags:
  - nvd
  - csaf
  - vex
  - red-hat
  - cve.org
  - score-dispute
epss: 0.00173
epssPercentile: 0.06654
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-15T21:48:10.598358Z'
scores:
  nvd: 7.8
  vendor: 5.5
  cna: 7.8
ingestedAt: '2026-10-15T22:48:25.496Z'
---

## Overview

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.

## Affected

- `linux_kernel >= 6.8.12, < 6.9`
- `linux_kernel >= 6.9.3, < 6.12.34`
- `linux_kernel >= 6.13, < 6.15.3`

## Remediation

Upgrade past the affected range:

- `linux_kernel 6.15.3`

## Vendor advisories

- **Red Hat VEX** · Moderate · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9 · updated 2026-10-16 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-38169.json)