CVE-2026-43133

Nested-guest state corruption via wrong VMCB selection

Published May 6, 2026 · Updated May 6, 2026

State-management error in Linux Kernel KVM nSVM allows local users to corrupt nested-guest state through VMLOAD or VMSAVE emulation. vmload_vmsave_interception() copies VMLOAD/VMSAVE fields through the current VMCB, so an L2 execution incorrectly uses vmcb02 instead of vmcb01. Reachability requires AMD nested SVM, an L2 guest, and an L1 that does not intercept the instructions; the state error crosses the guest boundary and interrupts the KVM workload.

CVSS severity7.9
High
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

State-management error in Linux Kernel KVM nSVM allows local users to corrupt nested-guest state through VMLOAD or VMSAVE emulation. vmload_vmsave_interception() copies VMLOAD/VMSAVE fields through the current VMCB, so an L2 execution incorrectly uses vmcb02 instead of vmcb01. Reachability requires AMD nested SVM, an L2 guest, and an L1 that does not intercept the instructions; the state error crosses the guest boundary and interrupts the KVM workload.

The record

CVE
CVE-2026-43133
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=5.13
  2. Affected versionversion=cc3ed80ae69f454c3d904af9f65394a540099723 <0004ecb798b30e90d7ebfe74efae2d9423315a64
  3. Affected versionversion=cc3ed80ae69f454c3d904af9f65394a540099723 <10063e1251c1485034a018236080792ad083dcc5
  4. Affected versionversion=cc3ed80ae69f454c3d904af9f65394a540099723 <127ccae2c185f62e6ecb4bf24f9cb307e9b9c619
  5. Affected versionversion=cc3ed80ae69f454c3d904af9f65394a540099723 <3880e331b0b31d0d5d3702b124f6c93539cd478a
  6. Affected versionversion=cc3ed80ae69f454c3d904af9f65394a540099723 <c3b7015000988ba35ecd5648f4b2283960f00543
  7. Affected versionversion=cc3ed80ae69f454c3d904af9f65394a540099723 <d464cf1ed900d47c85393d40b00017b6adfc2e6c
  8. Affected versionversion=cc3ed80ae69f454c3d904af9f65394a540099723 <fce2fd4a2ca05670a91015aacccf96a1c26268fd

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=5.13; version=cc3ed80ae69f454c3d904af9f65394a540099723 <0004ecb798b30e90d7ebfe74efae2d9423315a64; version=cc3ed80ae69f454c3d904af9f65394a540099723 <10063e1251c1485034a018236080792ad083dcc5; version=cc3ed80ae69f454c3d904af9f65394a540099723 <127ccae2c185f62e6ecb4bf24f9cb307e9b9c619; version=cc3ed80ae69f454c3d904af9f65394a540099723 <3880e331b0b31d0d5d3702b124f6c93539cd478a; version=cc3ed80ae69f454c3d904af9f65394a540099723 <c3b7015000988ba35ecd5648f4b2283960f00543; version=cc3ed80ae69f454c3d904af9f65394a540099723 <d464cf1ed900d47c85393d40b00017b6adfc2e6c; version=cc3ed80ae69f454c3d904af9f65394a540099723 <fce2fd4a2ca05670a91015aacccf96a1c26268fd

Published CVSS scores

7.9kernel.orgCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H
7.9redhat-SADPCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:L/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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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

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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