CVE-2026-64034

Summary

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().

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxca9c54d2d6a5ab2430c4eda364c77125d62e5e0f < a201c66edf2ebc6cfdc3813a889ba20fecebfae3affected
LinuxLinuxca9c54d2d6a5ab2430c4eda364c77125d62e5e0f < 70ad2dff8d052a85dfef15715b531f38a29108cfaffected
LinuxLinuxca9c54d2d6a5ab2430c4eda364c77125d62e5e0f < 566f42fb67a7ebfed6650e407e5b72e6b3e83bf7affected
LinuxLinuxca9c54d2d6a5ab2430c4eda364c77125d62e5e0f < 6180a06bbc99fd9114b8db4be6c4d46e40f046efaffected
LinuxLinuxca9c54d2d6a5ab2430c4eda364c77125d62e5e0f < 09ec063d87c2dd3fa6f3561361a017bd882e9f37affected
LinuxLinuxca9c54d2d6a5ab2430c4eda364c77125d62e5e0f < 3c4db56ccd13dd020fbf43afabaee74a40ec75e4affected
LinuxLinuxca9c54d2d6a5ab2430c4eda364c77125d62e5e0f < 35f0f0a2536a4d604b4dbad92c85c4a8fdebb870affected
LinuxLinux5.13affected
LinuxLinux0 < 5.13unaffected
LinuxLinux5.15.209 <= 5.15.*unaffected
LinuxLinux6.1.175 <= 6.1.*unaffected
LinuxLinux6.6.142 <= 6.6.*unaffected
LinuxLinux6.12.92 <= 6.12.*unaffected
LinuxLinux6.18.34 <= 6.18.*unaffected
LinuxLinux7.0.11 <= 7.0.*unaffected
LinuxLinux7.1 <= *unaffected

Weaknesses

References