CVE-2026-63877

Boot crash via null port-parent dereference

Published Jul 19, 2026 · Updated Jul 19, 2026

Null pointer dereference in the Linux Kernel DZ serial driver 6.5 allows a system crash when the first serial port initializes. The legacy-probed port has no parent device, yet serial_core_register_port reaches __dev_fwnode and dereferences a pointer derived from that null parent. The failure occurs during boot on DECstation systems with DZ serial hardware and prevents successful kernel initialization; no attacker-controlled trigger is reported.

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

Null pointer dereference in the Linux Kernel DZ serial driver 6.5 allows a system crash when the first serial port initializes. The legacy-probed port has no parent device, yet serial_core_register_port reaches __dev_fwnode and dereferences a pointer derived from that null parent. The failure occurs during boot on DECstation systems with DZ serial hardware and prevents successful kernel initialization; no attacker-controlled trigger is reported.

The record

CVE
CVE-2026-63877
Published
Jul 19, 2026
Updated
Jul 19, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
Unavailable
Attack vector
Unavailable
Privileges
Unavailable

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=6.5
  2. Affected versionversion=84a9582fd203063cd4d301204971ff2cd8327f1a <2ff0401ffddaccc85f758c8259912d686d052b31
  3. Affected versionversion=84a9582fd203063cd4d301204971ff2cd8327f1a <5c9fb95c8d6430d11dbb7b44fbe23222585cda86
  4. Affected versionversion=84a9582fd203063cd4d301204971ff2cd8327f1a <5d7a49d60b8fda66da60e240fd7315232fa1754f
  5. Affected versionversion=84a9582fd203063cd4d301204971ff2cd8327f1a <6f59646229490a93cda950017ad4bdfbfe770a1d
  6. Affected versionversion=84a9582fd203063cd4d301204971ff2cd8327f1a <c9e78361fe92fb64662fc3c8f34e2cdbb8c25bc6

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linux Kernelversion=6.5; version=84a9582fd203063cd4d301204971ff2cd8327f1a <2ff0401ffddaccc85f758c8259912d686d052b31; version=84a9582fd203063cd4d301204971ff2cd8327f1a <5c9fb95c8d6430d11dbb7b44fbe23222585cda86; version=84a9582fd203063cd4d301204971ff2cd8327f1a <5d7a49d60b8fda66da60e240fd7315232fa1754f; version=84a9582fd203063cd4d301204971ff2cd8327f1a <6f59646229490a93cda950017ad4bdfbfe770a1d; version=84a9582fd203063cd4d301204971ff2cd8327f1a <c9e78361fe92fb64662fc3c8f34e2cdbb8c25bc6

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

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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)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

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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