CVE-2026-43421

Local system crash via stale gadget parent

Published May 8, 2026 · Updated May 8, 2026

Null pointer dereference in the Linux kernel USB NCM gadget subsystem allows local users to crash the system during gadget disconnection. The f_ncm network device remains parented to a gadget device that is destroyed on disconnect, leaving dangling sysfs links that later dereference a null parent. Triggering requires local access and an active USB NCM gadget configuration; the documented consequence is a kernel crash rather than data access or privilege gain.

CVSS severity5.5
Medium
EPSS probability0.12%
Next 30 days · Sep 17, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Null pointer dereference in the Linux kernel USB NCM gadget subsystem allows local users to crash the system during gadget disconnection. The f_ncm network device remains parented to a gadget device that is destroyed on disconnect, leaving dangling sysfs links that later dereference a null parent. Triggering requires local access and an active USB NCM gadget configuration; the documented consequence is a kernel crash rather than data access or privilege gain.

The record

CVE
CVE-2026-43421
Published
May 8, 2026
Updated
May 8, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-476, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 8, 2026CVE publishedPublication date reported by the CVE source.
  2. May 8, 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=3.11
  2. Affected versionversion=40d133d7f542616cf9538508a372306e626a16e9 <85acaba2f42b557499bab3608307f17bf13beb69
  3. Affected versionversion=40d133d7f542616cf9538508a372306e626a16e9 <93f116c3393a22acab96ad1bef12b2572eb80ca4
  4. Affected versionversion=40d133d7f542616cf9538508a372306e626a16e9 <e584cb58a2ea7ff4d3a4bc43d5ca512ed3ecb77d
  5. Affected versionversion=40d133d7f542616cf9538508a372306e626a16e9 <ec35c1969650e7cb6c8a91020e568ed46e3551b0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=3.11; version=40d133d7f542616cf9538508a372306e626a16e9 <85acaba2f42b557499bab3608307f17bf13beb69; version=40d133d7f542616cf9538508a372306e626a16e9 <93f116c3393a22acab96ad1bef12b2572eb80ca4; version=40d133d7f542616cf9538508a372306e626a16e9 <e584cb58a2ea7ff4d3a4bc43d5ca512ed3ecb77d; version=40d133d7f542616cf9538508a372306e626a16e9 <ec35c1969650e7cb6c8a91020e568ed46e3551b0

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
5.5Canonical Ubuntu SecurityCVSS: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 11, 2026Sep 17, 2026
Latest reporting daySep 17, 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
T1499.004Endpoint Denial of Service: Application 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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Your stack

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