CVE-2026-31456

Local system crash via stale PUD descent

Published Apr 22, 2026 · Updated Apr 22, 2026

A race condition in Linux Kernel 6.12 and affected later branches allows local users to crash the kernel during concurrent page walking. walk_pud_range can observe a PUD while another thread splits and refaults its leaf, causing walk_pmd_range to descend into a vanished PMD range. Reproduction requires a concurrent page walk and refault, demonstrated by reading numa_maps while VFIO-PCI pins a process's large BAR for DMA.

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

A race condition in Linux Kernel 6.12 and affected later branches allows local users to crash the kernel during concurrent page walking. walk_pud_range can observe a PUD while another thread splits and refaults its leaf, causing walk_pmd_range to descend into a vanished PMD range. Reproduction requires a concurrent page walk and refault, demonstrated by reading numa_maps while VFIO-PCI pins a process's large BAR for DMA.

The record

CVE
CVE-2026-31456
Published
Apr 22, 2026
Updated
Apr 22, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-362, T1499
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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=6.12
  2. Affected versionversion=f9e54c3a2f5b79ecc57c7bc7d0d3521e461a2101 <38ec58670a0c5fc1edabdeccd857e586b7b3f318
  3. Affected versionversion=f9e54c3a2f5b79ecc57c7bc7d0d3521e461a2101 <3b89863c3fa482912911cd65a12a3aeef662c250
  4. Affected versionversion=f9e54c3a2f5b79ecc57c7bc7d0d3521e461a2101 <9bbbebd94dd5be25ec8c899d46ef01b33d5d22c0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=6.12; version=f9e54c3a2f5b79ecc57c7bc7d0d3521e461a2101 <38ec58670a0c5fc1edabdeccd857e586b7b3f318; version=f9e54c3a2f5b79ecc57c7bc7d0d3521e461a2101 <3b89863c3fa482912911cd65a12a3aeef662c250; version=f9e54c3a2f5b79ecc57c7bc7d0d3521e461a2101 <9bbbebd94dd5be25ec8c899d46ef01b33d5d22c0

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.

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

CWE-362Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
T1499Endpoint Denial of Service

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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