CVE-2026-63890

FCoE controller hang via zero-length descriptor

Published Jul 19, 2026 · Updated Jul 19, 2026

Improper input validation in Linux Kernel allows remote attackers to hang FCoE controller processing via a malformed FIP CVL frame. In fcoe_ctlr_recv_clr_vlink(), the default descriptor case advances its cursor by untrusted fip_dlen without rejecting a value smaller than the descriptor header, so a zero length leaves the loop position unchanged. Access requires an unauthenticated Layer 2 peer on the FCoE control VLAN; one frame can indefinitely block later FIP frames on the affected controller.

CVSS severityUnavailable
Unscored
EPSS probability0.22%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Linux Kernel allows remote attackers to hang FCoE controller processing via a malformed FIP CVL frame. In fcoe_ctlr_recv_clr_vlink(), the default descriptor case advances its cursor by untrusted fip_dlen without rejecting a value smaller than the descriptor header, so a zero length leaves the loop position unchanged. Access requires an unauthenticated Layer 2 peer on the FCoE control VLAN; one frame can indefinitely block later FIP frames on the affected controller.

The record

CVE
CVE-2026-63890
Published
Jul 19, 2026
Updated
Jul 19, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 19, 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=2.6.30
  2. Affected versionversion=97c8389d54b9665c38105ea72a428a44b97ff2f6 <0e3c6e5a8fc15a74dfb1e0c1df9f1da73600a81a
  3. Affected versionversion=97c8389d54b9665c38105ea72a428a44b97ff2f6 <14dd80a20a72ce334adcc2d67402360527065948
  4. Affected versionversion=97c8389d54b9665c38105ea72a428a44b97ff2f6 <549859a1131052b07dff11a448e9f3221a40f260
  5. Affected versionversion=97c8389d54b9665c38105ea72a428a44b97ff2f6 <80a0cd307205236ca28aa49bc553f58edcb9bf3a
  6. Affected versionversion=97c8389d54b9665c38105ea72a428a44b97ff2f6 <9eed1bd59937e6828b00d2f2dfef631d964f3636
  7. Affected versionversion=97c8389d54b9665c38105ea72a428a44b97ff2f6 <d179949d2175d2857d1c3a275a22bea58bcc5d36
  8. Affected versionversion=97c8389d54b9665c38105ea72a428a44b97ff2f6 <d537d29d51c8b808469e5adacf3e5a0092700738
  9. Affected versionversion=97c8389d54b9665c38105ea72a428a44b97ff2f6 <fda976f7390bb5d1e9b84ef11ebb17323038e0c6

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=2.6.30; version=97c8389d54b9665c38105ea72a428a44b97ff2f6 <0e3c6e5a8fc15a74dfb1e0c1df9f1da73600a81a; version=97c8389d54b9665c38105ea72a428a44b97ff2f6 <14dd80a20a72ce334adcc2d67402360527065948; version=97c8389d54b9665c38105ea72a428a44b97ff2f6 <549859a1131052b07dff11a448e9f3221a40f260; version=97c8389d54b9665c38105ea72a428a44b97ff2f6 <80a0cd307205236ca28aa49bc553f58edcb9bf3a; version=97c8389d54b9665c38105ea72a428a44b97ff2f6 <9eed1bd59937e6828b00d2f2dfef631d964f3636; version=97c8389d54b9665c38105ea72a428a44b97ff2f6 <d179949d2175d2857d1c3a275a22bea58bcc5d36; version=97c8389d54b9665c38105ea72a428a44b97ff2f6 <d537d29d51c8b808469e5adacf3e5a0092700738; version=97c8389d54b9665c38105ea72a428a44b97ff2f6 <fda976f7390bb5d1e9b84ef11ebb17323038e0c6

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.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
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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