CVE-2026-99178Public exploit

Guest panic via nested page-fault flag consumption

Published Oct 28, 2026 · Updated Oct 28, 2026

A race in Linux 6.18.50 x86 KVM page-fault handling allows local users to panic a guest via overlapping asynchronous faults and NMIs. In __kvm_handle_async_pf(), a kernel page fault inside an NMI consumes apf_reason.flags belonging to the interrupted asynchronous fault, triggering an interrupt-disabled panic. Reproduction requires asynchronous page-fault delivery and a precisely timed nested fault, demonstrated with perf user-stack sampling in a restored guest.

CVSS severityUnavailable
Unscored
EPSS probability0.17%
Next 30 days · Nov 1, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A race in Linux 6.18.50 x86 KVM page-fault handling allows local users to panic a guest via overlapping asynchronous faults and NMIs. In __kvm_handle_async_pf(), a kernel page fault inside an NMI consumes apf_reason.flags belonging to the interrupted asynchronous fault, triggering an interrupt-disabled panic. Reproduction requires asynchronous page-fault delivery and a precisely timed nested fault, demonstrated with perf user-stack sampling in a restored guest.

The record

CVE
CVE-2026-99178
Published
Oct 28, 2026
Updated
Oct 28, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
Unavailable

Timeline

How it unfolded

  1. Oct 28, 2026CVE publishedPublication date reported by the CVE source.
  2. Oct 28, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <6.18.59
  2. Affected versionversion=0 <7.2.13
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <81d99abe2bd81379abfb595e403bbbee6fbfc624
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b77e9622bbade9812e2090c66d25c372f515e921
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f45ee1ff6358a22d7e22a4c53cb3148ea97b10d9

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=0 <6.18.59; version=0 <7.2.13; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <81d99abe2bd81379abfb595e403bbbee6fbfc624; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b77e9622bbade9812e2090c66d25c372f515e921; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f45ee1ff6358a22d7e22a4c53cb3148ea97b10d9

Published CVSS scores

No CVSS assessment is available in this record.

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.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

T1499Endpoint Denial of Service

Public exploit references

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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