CVE-2026-99213

Kernel crash via vsock connection-state race

Published Oct 28, 2026 · Updated Oct 28, 2026

A race in Linux vsock allows local users to crash the kernel through connection resets during concurrent connection establishment. The vsock_connect() loop mistakes TCP_CLOSING for an unsuccessful connection and resets a socket still linked in connected_table, allowing reinsertion to corrupt the list. Triggering requires accessible AF_VSOCK support and racing connection activity; upstream reports kernel crashes, not demonstrated privilege escalation.

CVSS severityUnavailable
Unscored
EPSS probability0.13%
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 vsock allows local users to crash the kernel through connection resets during concurrent connection establishment. The vsock_connect() loop mistakes TCP_CLOSING for an unsuccessful connection and resets a socket still linked in connected_table, allowing reinsertion to corrupt the list. Triggering requires accessible AF_VSOCK support and racing connection activity; upstream reports kernel crashes, not demonstrated privilege escalation.

The record

CVE
CVE-2026-99213
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

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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=3.9
  2. Affected versionversion=d021c344051af91f42c5ba9fdedc176740cbd238 <44d1ca05d6094a5d75c671a0545249186d790b8d
  3. Affected versionversion=d021c344051af91f42c5ba9fdedc176740cbd238 <4f6ac74fa594a918d41255c941256e1d51592d3b
  4. Affected versionversion=d021c344051af91f42c5ba9fdedc176740cbd238 <c2c5359ef2c33684fa3f3652fd761a483db8d1e7

What conditions does exploitation require?

Attack vectorlocal
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=3.9; version=d021c344051af91f42c5ba9fdedc176740cbd238 <44d1ca05d6094a5d75c671a0545249186d790b8d; version=d021c344051af91f42c5ba9fdedc176740cbd238 <4f6ac74fa594a918d41255c941256e1d51592d3b; version=d021c344051af91f42c5ba9fdedc176740cbd238 <c2c5359ef2c33684fa3f3652fd761a483db8d1e7

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 exploitUnconfirmed

Weakness, pattern, technique

T1499Endpoint Denial of Service

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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