CVE-2026-74729

/// Technical description

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

soc: aspeed: lpc-snoop: Fix usercopy overflow in snoop_file_read

put_fifo_with_discard() acts as both producer and consumer on the kfifo:

it calls kfifo_skip() (advances out) and kfifo_put() (advances in) from

the IRQ handler without synchronizing with snoop_file_read(), which also

consumes via kfifo_to_user(). On SMP systems this concurrent access can

leave (in - out) larger than the ring buffer, so __kfifo_to_user()'s clamp

to (in - out) is ineffective and kfifo_copy_to_user() can attempt a

copy_to_user() past the kmalloc-2k backing store:

usercopy: Kernel memory exposure attempt detected from SLUB object

'kmalloc-2k' (offset 0, size 2049)!

kernel BUG at mm/usercopy.c!

Call trace:

usercopy_abort

__check_heap_object

__check_object_size

kfifo_copy_to_user

__kfifo_to_user

snoop_file_read

vfs_read

Serialize kfifo access with a per-channel spinlock shared between the

IRQ handler (producer)

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References