CVE-2026-64034

Description

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().

References

• https://git.kernel.org/stable/c/09ec063d87c2dd3fa6f3561361a017bd882e9f37
• https://git.kernel.org/stable/c/35f0f0a2536a4d604b4dbad92c85c4a8fdebb870
• https://git.kernel.org/stable/c/3c4db56ccd13dd020fbf43afabaee74a40ec75e4
• https://git.kernel.org/stable/c/566f42fb67a7ebfed6650e407e5b72e6b3e83bf7
• https://git.kernel.org/stable/c/6180a06bbc99fd9114b8db4be6c4d46e40f046ef