CVE-2026-43240

Kernel panic via unchecked IMA buffer range

Published May 6, 2026 · Updated May 6, 2026

Denial of service in the x86 kexec setup path in Linux Kernel allows local users to panic a second-stage kernel during a memory-limited boot. The setup path converts the carried IMA buffer address to a virtual pointer without first using pfn_range_is_mapped() to verify that its endpoint page frames remain mapped. Reachability requires an x86 kexec transition carrying an IMA measurement list and a mem= limit that excludes its physical range; the resulting page fault crashes the new kernel.

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 the x86 kexec setup path in Linux Kernel allows local users to panic a second-stage kernel during a memory-limited boot. The setup path converts the carried IMA buffer address to a virtual pointer without first using pfn_range_is_mapped() to verify that its endpoint page frames remain mapped. Reachability requires an x86 kexec transition carrying an IMA measurement list and a mem= limit that excludes its physical range; the resulting page fault crashes the new kernel.

The record

CVE
CVE-2026-43240
Published
May 6, 2026
Updated
May 6, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 6, 2026CVE publishedPublication date reported by the CVE source.
  2. May 6, 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=6.0
  2. Affected versionversion=b69a2afd5afce9bf6d56e349d6ab592c916e20f2 <22e460b6333a5f818b042ac89201f8e735556f4a
  3. Affected versionversion=b69a2afd5afce9bf6d56e349d6ab592c916e20f2 <37f18915a261afe84dab462624ed829cddb77a9b
  4. Affected versionversion=b69a2afd5afce9bf6d56e349d6ab592c916e20f2 <4d7a8f5f28187e3d2958b2a134473da2665207e7
  5. Affected versionversion=b69a2afd5afce9bf6d56e349d6ab592c916e20f2 <c5489d04337b47e93c0623e8145fcba3f5739efd
  6. Affected versionversion=b69a2afd5afce9bf6d56e349d6ab592c916e20f2 <d4a132f121c591b60dbaf57ea91f1faf11631fbc
  7. Affected versionversion=b69a2afd5afce9bf6d56e349d6ab592c916e20f2 <f8f73bf0f8a57ee9b86792456bd42079bc98c6b7

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=6.0; version=b69a2afd5afce9bf6d56e349d6ab592c916e20f2 <22e460b6333a5f818b042ac89201f8e735556f4a; version=b69a2afd5afce9bf6d56e349d6ab592c916e20f2 <37f18915a261afe84dab462624ed829cddb77a9b; version=b69a2afd5afce9bf6d56e349d6ab592c916e20f2 <4d7a8f5f28187e3d2958b2a134473da2665207e7; version=b69a2afd5afce9bf6d56e349d6ab592c916e20f2 <c5489d04337b47e93c0623e8145fcba3f5739efd; version=b69a2afd5afce9bf6d56e349d6ab592c916e20f2 <d4a132f121c591b60dbaf57ea91f1faf11631fbc; version=b69a2afd5afce9bf6d56e349d6ab592c916e20f2 <f8f73bf0f8a57ee9b86792456bd42079bc98c6b7

Published CVSS scores

5.5NIST NVDCVSS: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

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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