Linux Kernel Vulnerability in SMC Networking Feature

CVE-2025-40012

What is CVE-2025-40012?

A vulnerability in the Linux kernel's SMC (Shared Memory Communication) implementation arises from improper memory allocation. Specifically, the function smc_lo_register_dmb() mistakenly uses kzalloc() for DMB buffers, which are then passed to get_page() in the smc_rx_splice() call. This can trigger a warning due to the mismatch in expected memory types, potentially leading to a use-after-free condition if the allocated memory is released before the splice operation is completed. To mitigate this issue, it's recommended to use folio_alloc() instead, which ensures that the memory is page-backed and safely managed across system calls.

References