CVE-2026-53024

In the Linux kernel, the following vulnerability has been resolved:

greybus: raw: fix use-after-free if write is called after disconnect

If a user writes to the chardev after disconnect has been called, the

kernel panics with the following trace (with

CONFIG_INIT_ON_FREE_DEFAULT_ON=y):

BUG: kernel NULL pointer dereference, address: 0000000000000218

...

Call Trace:

<TASK>

gb_operation_create_common+0x61/0x180

gb_operation_create_flags+0x28/0xa0

gb_operation_sync_timeout+0x6f/0x100

raw_write+0x7b/0xc7 [gb_raw]

vfs_write+0xcf/0x420

? task_mm_cid_work+0x136/0x220

ksys_write+0x63/0xe0

do_syscall_64+0xa4/0x290

entry_SYSCALL_64_after_hwframe+0x77/0x7f

Disconnect calls gb_connection_destroy, which ends up freeing the

connection object. When gb_operation_sync is called in the write file

operations, its gets a freed connection as parameter and the kernel

panics.

The gb_connection_destroy cannot be moved out of the disconnect

function, as the Greybus subsystem expect all connections belonging to a

bundle to be destroyed when disconnect returns.

To prevent this bug, use a rw lock to synchronize access between write

and disconnect. This guarantees that the write function doesn't try

to use a disconnected connection.