CVE-2026-46076

Cross-guest state manipulation via misrouted VMMCALL

Published May 27, 2026 · Updated May 27, 2026

Improper VMMCALL handling in affected Linux KVM releases allows guest OS users to disrupt a parent guest from a nested AMD SVM guest. The nSVM VMMCALL path intercepts an unsupported L2 hypercall without forwarding it to L1 or raising #UD, so L0 handles it with L1 authority. Reachability requires nested AMD SVM, an L1 that does not intercept VMMCALL, direct L2 TLB-flush handling, and an unsupported Hyper-V hypercall; the result includes cross-domain state changes and workload hangs.

CVSS severity7.9
High
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

Improper VMMCALL handling in affected Linux KVM releases allows guest OS users to disrupt a parent guest from a nested AMD SVM guest. The nSVM VMMCALL path intercepts an unsupported L2 hypercall without forwarding it to L1 or raising #UD, so L0 handles it with L1 authority. Reachability requires nested AMD SVM, an L1 that does not intercept VMMCALL, direct L2 TLB-flush handling, and an unsupported Hyper-V hypercall; the result includes cross-domain state changes and workload hangs.

The record

CVE
CVE-2026-46076
Published
May 27, 2026
Updated
May 27, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 27, 2026CVE publishedPublication date reported by the CVE source.
  2. May 27, 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=3f4a812edf5cb0a50e65fbdfafdb3e688da18f16 <009c0f726abeaa67aad1d96b883bdce01d405ce2
  2. Affected versionversion=3f4a812edf5cb0a50e65fbdfafdb3e688da18f16 <5fb4a5f361565f5b629d8a8fe5288ce8463c5727
  3. Affected versionversion=3f4a812edf5cb0a50e65fbdfafdb3e688da18f16 <924d721fae95687acedbaf624a094ed0e8b67104
  4. Affected versionversion=3f4a812edf5cb0a50e65fbdfafdb3e688da18f16 <c36991c6f8d2ab56ee67aff04e3c357f45cfc76c
  5. Affected versionversion=6.2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=3f4a812edf5cb0a50e65fbdfafdb3e688da18f16 <009c0f726abeaa67aad1d96b883bdce01d405ce2; version=3f4a812edf5cb0a50e65fbdfafdb3e688da18f16 <5fb4a5f361565f5b629d8a8fe5288ce8463c5727; version=3f4a812edf5cb0a50e65fbdfafdb3e688da18f16 <924d721fae95687acedbaf624a094ed0e8b67104; version=3f4a812edf5cb0a50e65fbdfafdb3e688da18f16 <c36991c6f8d2ab56ee67aff04e3c357f45cfc76c; version=6.2

Published CVSS scores

7.9kernel.orgCVSS: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

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.

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Technologies

Your stack

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Your stack

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