CVE-2026-53042

fwctl: Fix class init ordering to avoid NULL pointer dereference on device removal

Published Jun 24, 2026 CVSS 3.1 · 5.5 Medium EPSS < 1% KEV · Not listed
Description
In the Linux kernel, the following vulnerability has been resolved:

fwctl: Fix class init ordering to avoid NULL pointer dereference on device removal

CXL is linked before fwctl in drivers/Makefile. Both use `module_init, so
`cxl_pci_driver_init()` runs first. When `cxl_pci_probe()` calls
`fwctl_register()` and then `device_add()`, fwctl_class is not yet
registered because fwctl_init() hasn't run, causing `class_to_subsys()` to
return NULL and skip knode_class initialization.

On device removal, `class_to_subsys()` returns non-NULL, and
`device_del()` calls `klist_del()` on the uninitialized knode, triggering
a NULL pointer dereference.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Ubuntu USN Ubuntu USN USN-8566-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8568-1 Linux kernel (OEM) vulnerabilities
Ubuntu USN Ubuntu USN USN-8569-1 Linux kernel (HWE) vulnerabilities
Ubuntu USN Ubuntu USN USN-8593-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8603-1 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-8618-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8663-1 Linux kernel (NVIDIA) vulnerabilities
Ubuntu USN Ubuntu USN USN-8728-1 Linux kernel (GCP) vulnerabilities
Ubuntu USN Ubuntu USN USN-8728-2 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-8728-3 Linux kernel (Oracle) vulnerabilities
History
Type Values Removed Values Added
Weaknesses CWE-476
Type Values Removed Values Added
Weaknesses CWE-824
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Low

Type Values Removed Values Added
Weaknesses CWE-476
Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: fwctl: Fix class init ordering to avoid NULL pointer dereference on device removal CXL is linked before fwctl in drivers/Makefile. Both use `module_init, so `cxl_pci_driver_init()` runs first. When `cxl_pci_probe()` calls `fwctl_register()` and then `device_add()`, fwctl_class is not yet registered because fwctl_init() hasn't run, causing `class_to_subsys()` to return NULL and skip knode_class initialization. On device removal, `class_to_subsys()` returns non-NULL, and `device_del()` calls `klist_del()` on the uninitialized knode, triggering a NULL pointer dereference.
Title fwctl: Fix class init ordering to avoid NULL pointer dereference on device removal
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References
Weaknesses

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
Jun 24, 2026, 4:29 PM
Reserved
Jun 9, 2026, 7:44 AM
Status
Analyzed
Published
Jun 24, 2026, 5:17 PM
Modified
Jul 14, 2026, 7:30 PM
Severity
Low
Public date
Jun 24, 2026, 12:00 AM