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NVD / CVE Program· CNA Linux

CVE-2022-49559: KVM: x86: Drop WARNs that assert a triple fault never "escapes" from L2

Noroxi assessment

Priority: Monitor (action score 22/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.29% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 45846661d10422ce9e22da21f8277540b29eca22, 7de373c9b48229e428ecdb8fbde269c5a8617fd2, 8d3a2aa0976f57320ba89baf9d57fb158dd0cd0d.

Low priority for now. Upgrade to Linux Linux 45846661d10422ce9e22da21f8277540b29eca22, 7de373c9b48229e428ecdb8fbde269c5a8617fd2, 8d3a2aa0976f57320ba89baf9d57fb158dd0cd0d or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Drop WARNs that assert a triple fault never "escapes" from L2 Remove WARNs that sanity check that KVM never lets a triple fault for L2 escape and incorrectly end up in L1. In normal operation, the sanity check is perfectly valid, but it incorrectly assumes that it's impossible for userspace to induce KVM_REQ_TRIPLE_FAULT without bouncing through KVM_RUN (which guarantees kvm_check_nested_state() will see and handle the triple fault). The WARN can currently be triggered if userspace injects a machine check while L2 is active and CR4.MCE=0. And a future fix to allow save/restore of KVM_REQ_TRIPLE_FAULT, e.g. so that a synthesized triple fault isn't lost on migration, will make it trivially easy for userspace to trigger the WARN. Clearing KVM_REQ_TRIPLE_FAULT when forcibly leaving guest mode is tempting, but wrong, especially if/when the request is saved/restored, e.g. if userspace restores events (including a triple fault) and then restores nested state (which may forcibly leave guest mode). Ignoring the fact that KVM doesn't currently provide the necessary APIs, it's userspace's responsibility to manage pending events during save/restore. ------------[ cut here ]------------ WARNING: CPU: 7 PID: 1399 at arch/x86/kvm/vmx/nested.c:4522 nested_vmx_vmexit+0x7fe/0xd90 [kvm_intel] Modules linked in: kvm_intel kvm irqbypass CPU: 7 PID: 1399 Comm: state_test Not tainted 5.17.0-rc3+ #808 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:nested_vmx_vmexit+0x7fe/0xd90 [kvm_intel] Call Trace: <TASK> vmx_leave_nested+0x30/0x40 [kvm_intel] vmx_set_nested_state+0xca/0x3e0 [kvm_intel] kvm_arch_vcpu_ioctl+0xf49/0x13e0 [kvm] kvm_vcpu_ioctl+0x4b9/0x660 [kvm] __x64_sys_ioctl+0x83/0xb0 do_syscall_64+0x3b/0xc0 entry_SYSCALL_64_after_hwframe+0x44/0xae </TASK> ---[ end trace 0000000000000000 ]---

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Feb 26, 2025
Updated
Jun 17, 2026
EPSS
0.2% · 22th percentile
CWE
—

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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When you'll hear from us

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  • when exploit code appears or is weaponized
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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel5.13 and later · before 5.15.45
  • linux linux kernel5.16 and later · before 5.17.13
  • linux linux kernel5.18 and later · before 5.18.2

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 5.13affected
    • cb6a32c2b8777ad31a02e585584d869251a790e3 and later · before 8d3a2aa0976f57320ba89baf9d57fb158dd0cd0daffected · git
    • cb6a32c2b8777ad31a02e585584d869251a790e3 and later · before f476a59d5c86c02a79eef893c6da86735f2977acaffected · git
    • cb6a32c2b8777ad31a02e585584d869251a790e3 and later · before 7de373c9b48229e428ecdb8fbde269c5a8617fd2affected · git
    • cb6a32c2b8777ad31a02e585584d869251a790e3 and later · before 45846661d10422ce9e22da21f8277540b29eca22affected · git
    • before 5.13not affected · semver
    • 5.15.45 and later · up to and including 5.15.*not affected · semver
    • 5.17.13 and later · up to and including 5.17.*not affected · semver
    • 5.18.2 and later · up to and including 5.18.*not affected · semver
    • 5.19 and laternot affected · original_commit_for_fix

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 5.18.2-15.18.2-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2022-49557Feb 26, 2025 · x86/fpu: KVM: Set the base guest FPU uABI size to sizeof(struct kvm_xsave)
    22Monitor
  • ← EarlierCVE-2022-49558Feb 26, 2025 · netfilter: nf_tables: double hook unregistration in netns path
    22Monitor
  • Later →CVE-2022-49560Feb 26, 2025 · exfat: check if cluster num is valid
    28Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux45846661d10422ce9e22da21f8277540b29eca22Vendor (CNA)
Linux Linux7de373c9b48229e428ecdb8fbde269c5a8617fd2Vendor (CNA)
Linux Linux8d3a2aa0976f57320ba89baf9d57fb158dd0cd0dVendor (CNA)
Linux Linuxf476a59d5c86c02a79eef893c6da86735f2977acVendor (CNA)
debian:linux5.18.2-1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (3 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records