CVE-2026-64034

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

net: mana: Fix TOCTOU double-fetch of hwc_msg_id from DMA buffer

In mana_hwc_rx_event_handler(), resp->response.hwc_msg_id is read from

DMA-coherent memory and bounds-checked, then mana_hwc_handle_resp()

re-reads the same field from the same DMA buffer for test_bit() and

pointer arithmetic.

DMA-coherent memory is mapped uncacheable on x86 and is shared,

unencrypted, in Confidential VMs (SEV-SNP/TDX), so each load goes

directly to host-visible memory. A H/W can modify the value

between the check and the use, bypassing the bounds validation.

Fix this by reading hwc_msg_id exactly once using READ_ONCE() into a

stack-local variable in mana_hwc_rx_event_handler(), and passing the

validated value as a parameter to mana_hwc_handle_resp().