Executive brief
A vulnerability in the Linux kernel could allow a local user to cause a system crash. The issue occurs when the system handles certain hardware or software configuration nodes that haven't been properly cleared in memory. This could lead to a denial-of-service, impacting the availability of the affected system.
Technical details
The vulnerability exists in the fwnode_init() function within the Linux kernel's driver core. When a firmware node (fwnode) is allocated on the stack or heap using a non-zeroing allocation function, the 'secondary' pointer remains uninitialized. Because this pointer may contain random memory values that are neither NULL nor error codes, subsequent calls to functions like dev_to_swnode() may attempt to dereference this invalid memory address. This results in a kernel oops or system crash. The fix involves explicitly setting fwnode->secondary to NULL during initialization in fwnode_init().
Affected products
- Linux Linux Kernel 5.11 to 6.18.34
Timeline
- 2026-05-06: other: Patch submitted by Bartosz Golaszewski
- 2026-07-24: advisory: CVE-2026-64220 published by NVD
References
- https://git.kernel.org/stable/c/215c90ee656114f5e8c32408228d97082f8e0eef
- https://git.kernel.org/stable/c/34bf74b1fd2e4a44e27821a329204caf09df2976
- https://git.kernel.org/stable/c/371f53925a6714d0aa35f1aefdffc3e8cd62f480
- https://git.kernel.org/stable/c/3f1024deeab3b5443c29b3de4fe475e87309b8fa
- https://git.kernel.org/stable/c/508fd8ab158abd04b7f7d0f707cd6d6c405df4ea
- https://git.kernel.org/stable/c/f0e211d6539fae800217c10797993b7592d6ab01
- https://git.kernel.org/stable/c/f59e686c778cb41b8f7aa8fab2afd6a01afb3d47