CVE-2026-31438

Kernel crash via unsupported ITER_KVEC dispatch

Published Apr 22, 2026 · Updated Apr 22, 2026

Denial of service in Linux Kernel allows local users to crash the system by writing a process core dump to a 9P filesystem. The netfs_limit_iter() path accepts ITER_KVEC from __kernel_write() but dispatches only folioq, bvec, and xarray iterators, so its default branch executes BUG(). The path requires a locally triggered process crash whose core dump destination is a 9P filesystem, and the resulting kernel BUG interrupts the host.

CVSS severity5.5
Medium
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Linux Kernel allows local users to crash the system by writing a process core dump to a 9P filesystem. The netfs_limit_iter() path accepts ITER_KVEC from __kernel_write() but dispatches only folioq, bvec, and xarray iterators, so its default branch executes BUG(). The path requires a locally triggered process crash whose core dump destination is a 9P filesystem, and the resulting kernel BUG interrupts the host.

The record

CVE
CVE-2026-31438
Published
Apr 22, 2026
Updated
Apr 22, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-476, 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=6.8
  2. Affected versionversion=cae932d3aee55035a54415dcea8e7ecf2ec469b5 <00d6df7115f6972370974212de9088087820802e
  3. Affected versionversion=cae932d3aee55035a54415dcea8e7ecf2ec469b5 <18c2e20b42dd21db599e42d05ddaeeb647b2bb6d
  4. Affected versionversion=cae932d3aee55035a54415dcea8e7ecf2ec469b5 <4bc2d72c7695cedf6d4e1a558924903c2b28a78e
  5. Affected versionversion=cae932d3aee55035a54415dcea8e7ecf2ec469b5 <67e467a11f62ff64ad219dc6aa5459e132c79d14

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=6.8; version=cae932d3aee55035a54415dcea8e7ecf2ec469b5 <00d6df7115f6972370974212de9088087820802e; version=cae932d3aee55035a54415dcea8e7ecf2ec469b5 <18c2e20b42dd21db599e42d05ddaeeb647b2bb6d; version=cae932d3aee55035a54415dcea8e7ecf2ec469b5 <4bc2d72c7695cedf6d4e1a558924903c2b28a78e; version=cae932d3aee55035a54415dcea8e7ecf2ec469b5 <67e467a11f62ff64ad219dc6aa5459e132c79d14

Published CVSS scores

5.5NVDCVSS: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.

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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

CWE-476NULL Pointer Dereference
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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