CVE-2026-53042

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. Whencxl_pci_probe()callsfwctl_register()and thendevice_add(), fwctl_class is not yet registered because fwctl_init() hasnt 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.

Weakness

The product accesses or uses a pointer that has not been initialized.

Affected Software

Extended Description

If the pointer contains an uninitialized value, then the value might not point to a valid memory location. This could cause the product to read from or write to unexpected memory locations, leading to a denial of service. If the uninitialized pointer is used as a function call, then arbitrary functions could be invoked. If an attacker can influence the portion of uninitialized memory that is contained in the pointer, this weakness could be leveraged to execute code or perform other attacks. Depending on memory layout, associated memory management behaviors, and product operation, the attacker might be able to influence the contents of the uninitialized pointer, thus gaining more fine-grained control of the memory location to be accessed.

References

• https://git.kernel.org/stable/c/1075f2f590fdac147f8b8010c35b606564b5c7d7
• https://git.kernel.org/stable/c/a28f56988c8e5bb9375806a5cfb0bf54d662ae3f
• https://git.kernel.org/stable/c/a55f80233f384dc89ef3425b2e1dd0e6d44bcf29