CVE-2025-38170

Service interruption via stale SME CPU state

Published Jul 3, 2025 · Updated May 11, 2026

Race condition in the arm64 SME trap handler in the Linux kernel allows local users to interrupt service by exercising SME with traps enabled. Preemption and CPU migration can leave TIF_SME set while TIF_FOREIGN_FPSTATE is clear, causing do_sme_acc() to reuse stale FPSIMD/SVE/SME CPU state instead of reloading saved state. Reachability requires local low-privilege code on an arm64 system with SME support and a precisely timed migration; the documented result is a kernel warning and availability loss.

CVSS severity5.5
Medium
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

Race condition in the arm64 SME trap handler in the Linux kernel allows local users to interrupt service by exercising SME with traps enabled. Preemption and CPU migration can leave TIF_SME set while TIF_FOREIGN_FPSTATE is clear, causing do_sme_acc() to reuse stale FPSIMD/SVE/SME CPU state instead of reloading saved state. Reachability requires local low-privilege code on an arm64 system with SME support and a precisely timed migration; the documented result is a kernel warning and availability loss.

The record

CVE
CVE-2025-38170
Published
Jul 3, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 3, 2025CVE publishedPublication date reported by the CVE source.
  2. May 11, 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=5.19
  2. Affected versionversion=8bd7f91c03d886f41d35f6108078d20be5a4a1bd <43be952e885476dafb74aa832c0847b2f4f650c6
  3. Affected versionversion=8bd7f91c03d886f41d35f6108078d20be5a4a1bd <6103f9ba51a59afb5a0f32299c837377c5a5a693
  4. Affected versionversion=8bd7f91c03d886f41d35f6108078d20be5a4a1bd <c4a4786d93e99517d6f10ed56b9ffba4ce88d3b3
  5. Affected versionversion=8bd7f91c03d886f41d35f6108078d20be5a4a1bd <d3eaab3c70905c5467e5c4ea403053d67505adeb
  6. Affected versionversion=8bd7f91c03d886f41d35f6108078d20be5a4a1bd <de89368de3894a8db27caeb8fd902ba1c49f696a

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.19; version=8bd7f91c03d886f41d35f6108078d20be5a4a1bd <43be952e885476dafb74aa832c0847b2f4f650c6; version=8bd7f91c03d886f41d35f6108078d20be5a4a1bd <6103f9ba51a59afb5a0f32299c837377c5a5a693; version=8bd7f91c03d886f41d35f6108078d20be5a4a1bd <c4a4786d93e99517d6f10ed56b9ffba4ce88d3b3; version=8bd7f91c03d886f41d35f6108078d20be5a4a1bd <d3eaab3c70905c5467e5c4ea403053d67505adeb; version=8bd7f91c03d886f41d35f6108078d20be5a4a1bd <de89368de3894a8db27caeb8fd902ba1c49f696a

Published CVSS scores

5.5UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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

T1499Endpoint Denial of Service

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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