CVE-2025-38169

Local state corruption via SMSTOP register reset

Published Jul 3, 2025 · Updated Aug 5, 2026

State corruption in arm64 FPSIMD handling in Linux allows local users to corrupt kernel-managed register state during a context switch. fpsimd_thread_switch() restores kernel FPSIMD state while the CPU remains in streaming SVE mode, then fpsimd_flush_cpu_state() executes SMSTOP; leaving streaming mode resets FPSIMD, SVE, and SME registers and overwrites the restored state. This requires an arm64 system with SME and a context switch to a thread holding kernel FPSIMD state; systems without SME are unaffected.

CVSS severity7.8
High
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

State corruption in arm64 FPSIMD handling in Linux allows local users to corrupt kernel-managed register state during a context switch. fpsimd_thread_switch() restores kernel FPSIMD state while the CPU remains in streaming SVE mode, then fpsimd_flush_cpu_state() executes SMSTOP; leaving streaming mode resets FPSIMD, SVE, and SME registers and overwrites the restored state. This requires an arm64 system with SME and a context switch to a thread holding kernel FPSIMD state; systems without SME are unaffected.

The record

CVE
CVE-2025-38169
Published
Jul 3, 2025
Updated
Aug 5, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1565
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 3, 2025CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=25b90cd122d546823da90b916f7c3289dfe83a99
  2. Affected versionversion=6.10
  3. Affected versionversion=6.8.12 <6.9
  4. Affected versionversion=6.9.3 <6.10
  5. Affected versionversion=e003c485ac82a9f8de4204912ed059ac6dd4257c
  6. Affected versionversion=e92bee9f861b466c676f0200be3e46af7bc4ac6b <01098d893fa8a6edb2b56e178b798e3e6b674f02
  7. Affected versionversion=e92bee9f861b466c676f0200be3e46af7bc4ac6b <55d52af498daea75aa03ba9b7e444c8ae495ac20
  8. Affected versionversion=e92bee9f861b466c676f0200be3e46af7bc4ac6b <a305821f597ec943849d3e53924adb88c61ed682

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=25b90cd122d546823da90b916f7c3289dfe83a99; version=6.10; version=6.8.12 <6.9; version=6.9.3 <6.10; version=e003c485ac82a9f8de4204912ed059ac6dd4257c; version=e92bee9f861b466c676f0200be3e46af7bc4ac6b <01098d893fa8a6edb2b56e178b798e3e6b674f02; version=e92bee9f861b466c676f0200be3e46af7bc4ac6b <55d52af498daea75aa03ba9b7e444c8ae495ac20; version=e92bee9f861b466c676f0200be3e46af7bc4ac6b <a305821f597ec943849d3e53924adb88c61ed682

Published CVSS scores

7.0Amazon LinuxCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
7.8LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
5.5NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
3.3SUSECVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1565Data Manipulation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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