CVE-2026-98526Hinoki check available

Kernel crash via insufficient LLC frame headroom

Published Oct 18, 2026 · Updated Oct 18, 2026

Headroom underflow in Linux LLC allows remote attackers on the local network to crash the kernel via LLC traffic on VLAN devices. The llc_alloc_frame() function reserves space based on device type rather than actual header requirements, so stacked VLAN and Ethernet headers exhaust the allocated headroom in eth_header(). Exploitation requires Layer-2 access, CONFIG_LLC2 enabled, and a non-offloaded VLAN path that generates an automatic LLC response.

CVSS severityUnavailable
Unscored
EPSS probability0.22%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Headroom underflow in Linux LLC allows remote attackers on the local network to crash the kernel via LLC traffic on VLAN devices. The llc_alloc_frame() function reserves space based on device type rather than actual header requirements, so stacked VLAN and Ethernet headers exhaust the allocated headroom in eth_header(). Exploitation requires Layer-2 access, CONFIG_LLC2 enabled, and a non-offloaded VLAN path that generates an automatic LLC response.

The record

CVE
CVE-2026-98526
Published
Oct 18, 2026
Updated
Oct 18, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Oct 18, 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=2.6.34
  2. Affected versionversion=bf9ae5386bca8836c16e69ab8fdbe46767d7452a <018020f5a48cc86fdd6dc2d380f6c70443ae7639
  3. Affected versionversion=bf9ae5386bca8836c16e69ab8fdbe46767d7452a <16ceac2daa89dd16917bc488ab05b9dd6961a603
  4. Affected versionversion=bf9ae5386bca8836c16e69ab8fdbe46767d7452a <1937222c2511ac91377d39f28106c34734f5f8c6
  5. Affected versionversion=bf9ae5386bca8836c16e69ab8fdbe46767d7452a <3361c93e417384ebf28003e0fb6d5304653d3b05
  6. Affected versionversion=bf9ae5386bca8836c16e69ab8fdbe46767d7452a <3a3f57c4061d9e9cc3bc04205d36ce41ae3406c1
  7. Affected versionversion=bf9ae5386bca8836c16e69ab8fdbe46767d7452a <72b5b9a28b996e09b8b5b944370c79851bb68f52
  8. Affected versionversion=bf9ae5386bca8836c16e69ab8fdbe46767d7452a <7c38524b2b2456bd33cb360420da6cbf9cad1b33
  9. Affected versionversion=bf9ae5386bca8836c16e69ab8fdbe46767d7452a <e06f8b6e27cc616d3c587e9784c4a033eb310a16

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.34; version=bf9ae5386bca8836c16e69ab8fdbe46767d7452a <018020f5a48cc86fdd6dc2d380f6c70443ae7639; version=bf9ae5386bca8836c16e69ab8fdbe46767d7452a <16ceac2daa89dd16917bc488ab05b9dd6961a603; version=bf9ae5386bca8836c16e69ab8fdbe46767d7452a <1937222c2511ac91377d39f28106c34734f5f8c6; version=bf9ae5386bca8836c16e69ab8fdbe46767d7452a <3361c93e417384ebf28003e0fb6d5304653d3b05; version=bf9ae5386bca8836c16e69ab8fdbe46767d7452a <3a3f57c4061d9e9cc3bc04205d36ce41ae3406c1; version=bf9ae5386bca8836c16e69ab8fdbe46767d7452a <72b5b9a28b996e09b8b5b944370c79851bb68f52; version=bf9ae5386bca8836c16e69ab8fdbe46767d7452a <7c38524b2b2456bd33cb360420da6cbf9cad1b33; version=bf9ae5386bca8836c16e69ab8fdbe46767d7452a <e06f8b6e27cc616d3c587e9784c4a033eb310a16

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.

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No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
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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