CVE-2026-31466

Local kernel crash via missing memory barrier

Published Apr 22, 2026 · Updated Apr 22, 2026

Race condition in the Linux Kernel allows local users to crash affected arm64 systems during concurrent memory-management operations. The softleaf_to_folio() and softleaf_to_page() paths read a migration-entry tail page without the smp_rmb() needed to order compound-head and page-flag observations. The fault requires a race between mTHP folio splitting and zap_nonpresent_ptes(); winning it reaches an unlocked folio and triggers a kernel warning or, on older kernels, a BUG_ON panic.

CVSS severity4.7
Medium
EPSS probability0.09%
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 Linux Kernel allows local users to crash affected arm64 systems during concurrent memory-management operations. The softleaf_to_folio() and softleaf_to_page() paths read a migration-entry tail page without the smp_rmb() needed to order compound-head and page-flag observations. The fault requires a race between mTHP folio splitting and zap_nonpresent_ptes(); winning it reaches an unlocked folio and triggers a kernel warning or, on older kernels, a BUG_ON panic.

The record

CVE
CVE-2026-31466
Published
Apr 22, 2026
Updated
Apr 22, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-362, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 22, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 22, 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=4.5
  2. Affected versionversion=e9b61f19858a5d6c42ce2298cf138279375d0d9b <426ee10711586617da869c8bb798214965337617
  3. Affected versionversion=e9b61f19858a5d6c42ce2298cf138279375d0d9b <4c5e7f0fcd592801c9cc18f29f80fbee84eb8669
  4. Affected versionversion=e9b61f19858a5d6c42ce2298cf138279375d0d9b <722cfaf6b31d31123439e67b5deac6b1261a3dea
  5. Affected versionversion=e9b61f19858a5d6c42ce2298cf138279375d0d9b <7ad1997b9bc8032603df8f091761114479285769
  6. Affected versionversion=e9b61f19858a5d6c42ce2298cf138279375d0d9b <7ddcf4a245c1c5a91fdd9698757e3d95179ffe41
  7. Affected versionversion=e9b61f19858a5d6c42ce2298cf138279375d0d9b <8bfb8414e9f2ce6f5f2f0e3d0da52f2d132128e7
  8. Affected versionversion=e9b61f19858a5d6c42ce2298cf138279375d0d9b <b8c49ad888892ad7b77062b9c102b799a3e9b4f8
  9. Affected versionversion=e9b61f19858a5d6c42ce2298cf138279375d0d9b <f1acf5887c2bbaf998dc3fe32c72b7a8b84a3ddd

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=4.5; version=e9b61f19858a5d6c42ce2298cf138279375d0d9b <426ee10711586617da869c8bb798214965337617; version=e9b61f19858a5d6c42ce2298cf138279375d0d9b <4c5e7f0fcd592801c9cc18f29f80fbee84eb8669; version=e9b61f19858a5d6c42ce2298cf138279375d0d9b <722cfaf6b31d31123439e67b5deac6b1261a3dea; version=e9b61f19858a5d6c42ce2298cf138279375d0d9b <7ad1997b9bc8032603df8f091761114479285769; version=e9b61f19858a5d6c42ce2298cf138279375d0d9b <7ddcf4a245c1c5a91fdd9698757e3d95179ffe41; version=e9b61f19858a5d6c42ce2298cf138279375d0d9b <8bfb8414e9f2ce6f5f2f0e3d0da52f2d132128e7; version=e9b61f19858a5d6c42ce2298cf138279375d0d9b <b8c49ad888892ad7b77062b9c102b799a3e9b4f8; version=e9b61f19858a5d6c42ce2298cf138279375d0d9b <f1acf5887c2bbaf998dc3fe32c72b7a8b84a3ddd

Published CVSS scores

4.7NIST NVDCVSS:3.1/AV:L/AC:H/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.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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