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Linux KernelOperating system · Linux

CVE-2026-53042

MEDIUM · 5.5 CVSS v3.1 Published 2026-06-24
Fix available
A fix is available. Upgrade to 6.18.33 / 7.0.10 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click Patch available 8 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A kernel module initialization ordering bug causes a NULL pointer dereference when CXL devices are removed. Since CXL is linked before fwctl in the Makefile, cxl_pci_probe() calls fwctl_register() before fwctl_init() registers the fwctl_class. This leaves knode_class uninitialized. When the device is later removed, class_to_subsys() returns valid (fwctl_init has since run), causing device_del() to call klist_del() on the uninitialized knode, triggering the NULL dereference.

MitigationThis is a kernel bug requiring a code fix to ensure proper initialization ordering between CXL and fwctl modules. Kernel update to a version containing the fix is required.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:>= 6.15, < 6.18.33>= 6.19, < 7.0.10

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check kernel version
    Run 'uname -r' or 'cat /proc/version' to get the running kernel version
    Affected if Version falls within >= 6.15, < 6.18.33 or >= 6.19, < 7.0.10
  2. Verify CXL support is enabled
    Check if CONFIG_CXL is set in /boot/config-$(uname -r) or check /sys/module/cxl exists, or run 'lsmod | grep cxl'
    Affected if CXL support is built into the kernel or loaded as a module
  3. Verify fwctl support is enabled
    Check if CONFIG_FWCTL is set in /boot/config-$(uname -r) or check /sys/class/fwctl exists
    Affected if fwctl support is built into the kernel or available as a module
  4. Check for active CXL devices
    Run 'cxl list' (if cxl utility installed) or check 'ls -la /sys/bus/cxl/devices/' for CXL device entries
    Affected if Any CXL devices are currently present in the system

The system is affected if the kernel version is within the affected range AND CXL support is enabled AND fwctl support is enabled AND CXL devices are actively registered.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 6.18.33 / 7.0.10 or later
Fixed in 6.18.337.0.10
Vendor patch git.kernel.org →
Interim mitigation

This is a kernel bug requiring a code fix to ensure proper initialization ordering between CXL and fwctl modules. Kernel update to a version containing the fix is required.

Recommended fix High confidence

6.18.33 or 7.0.10

  1. Upgrade Linux kernel to version 6.18.33 or later for the 6.18 branch
  2. Alternatively, upgrade to version 7.0.10 or later for the 7.0 branch
  3. Verify the fix is included by checking that the fwctl class initialization ordering is corrected in the release notes or commit log
Caveat Kernel upgrades may require system reboot and could introduce compatibility changes with existing kernel modules or drivers

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Linux Kernel Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing8.0 h
  • Review / QA2.0 h
16.0 hours of engineering $2,680
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-53042 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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