CVE-2026-63876

Boot crash via null parent-device dereference

Published Jul 19, 2026 · Updated Jul 19, 2026

NULL pointer dereference in the Linux Kernel 6.5 zs serial driver causes the system to crash as the first serial port initializes. The driver passes a port whose parent device is null into serial_base_ctrl_add, which derives and dereferences a pointer from that missing parent. The failure is limited to boot-time initialization of the legacy DECstation Z85C30 path and interrupts startup rather than exposing or modifying data.

CVSS severity5.5
Medium
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 6.5 zs serial driver causes the system to crash as the first serial port initializes. The driver passes a port whose parent device is null into serial_base_ctrl_add, which derives and dereferences a pointer from that missing parent. The failure is limited to boot-time initialization of the legacy DECstation Z85C30 path and interrupts startup rather than exposing or modifying data.

The record

CVE
CVE-2026-63876
Published
Jul 19, 2026
Updated
Jul 19, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-476
Attack vector
local
Privileges
authenticated

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 <237dc8c08de3cb293b6607aaee8b13b3a671e267
  3. Affected versionversion=84a9582fd203063cd4d301204971ff2cd8327f1a <4dc9f1517503c883d5ce25b7ab29d177d05edc6a
  4. Affected versionversion=84a9582fd203063cd4d301204971ff2cd8327f1a <6a83d5e24a84e746425cd93539130e5f7381ef47
  5. Affected versionversion=84a9582fd203063cd4d301204971ff2cd8327f1a <7cac59d08a73cb866ec51a483a6f3fe0f531947c
  6. Affected versionversion=84a9582fd203063cd4d301204971ff2cd8327f1a <bb2040484f90f91b717060e1a66026cc4287bcf0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=6.5; version=84a9582fd203063cd4d301204971ff2cd8327f1a <237dc8c08de3cb293b6607aaee8b13b3a671e267; version=84a9582fd203063cd4d301204971ff2cd8327f1a <4dc9f1517503c883d5ce25b7ab29d177d05edc6a; version=84a9582fd203063cd4d301204971ff2cd8327f1a <6a83d5e24a84e746425cd93539130e5f7381ef47; version=84a9582fd203063cd4d301204971ff2cd8327f1a <7cac59d08a73cb866ec51a483a6f3fe0f531947c; version=84a9582fd203063cd4d301204971ff2cd8327f1a <bb2040484f90f91b717060e1a66026cc4287bcf0

Published CVSS scores

5.5Red HatCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

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)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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