CVE-2022-49559

Local denial of service via KVM WARN

Published Feb 26, 2025 · Updated May 11, 2026

Improper nested-state handling in Linux KVM 5.13 through 5.18 allows local users to trigger a kernel warning via crafted VM state. The nested VM-exit paths assume KVM_REQ_TRIPLE_FAULT cannot escape L2, but a userspace-injected machine check with L2 active and CR4.MCE=0 violates that assumption and reaches WARN(). The default result is a logged warning; hosts configured with panic_on_warn convert it into a kernel panic and service interruption.

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

What happened

Improper nested-state handling in Linux KVM 5.13 through 5.18 allows local users to trigger a kernel warning via crafted VM state. The nested VM-exit paths assume KVM_REQ_TRIPLE_FAULT cannot escape L2, but a userspace-injected machine check with L2 active and CR4.MCE=0 violates that assumption and reaches WARN(). The default result is a logged warning; hosts configured with panic_on_warn convert it into a kernel panic and service interruption.

The record

CVE
CVE-2022-49559
Published
Feb 26, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 26, 2025CVE publishedPublication date reported by the CVE source.
  2. May 11, 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=cb6a32c2b8777ad31a02e585584d869251a790e3 <45846661d10422ce9e22da21f8277540b29eca22
  3. Affected versionversion=cb6a32c2b8777ad31a02e585584d869251a790e3 <7de373c9b48229e428ecdb8fbde269c5a8617fd2
  4. Affected versionversion=cb6a32c2b8777ad31a02e585584d869251a790e3 <8d3a2aa0976f57320ba89baf9d57fb158dd0cd0d
  5. Affected versionversion=cb6a32c2b8777ad31a02e585584d869251a790e3 <f476a59d5c86c02a79eef893c6da86735f2977ac

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.13; version=cb6a32c2b8777ad31a02e585584d869251a790e3 <45846661d10422ce9e22da21f8277540b29eca22; version=cb6a32c2b8777ad31a02e585584d869251a790e3 <7de373c9b48229e428ecdb8fbde269c5a8617fd2; version=cb6a32c2b8777ad31a02e585584d869251a790e3 <8d3a2aa0976f57320ba89baf9d57fb158dd0cd0d; version=cb6a32c2b8777ad31a02e585584d869251a790e3 <f476a59d5c86c02a79eef893c6da86735f2977ac

Published CVSS scores

5.5CanonicalCVSS: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 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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