CRITICAL: CVE-2026-64034 (CVSS 9.3) — multiple products

CVE: CVE-2026-64034

CVSS: 9.3 (3.1) — CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Severity: CRITICAL

Status: Critical advisory

Affected

_See vendor advisory_

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().

Verified Sources

• NVD entry
• GitHub Advisory
• MITRE

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
• https://git.kernel.org/stable/c/70ad2dff8d052a85dfef15715b531f38a29108cf
• https://git.kernel.org/stable/c/a201c66edf2ebc6cfdc3813a889ba20fecebfae3

_Validated by the Lyrie Threat Intelligence Pipeline — 3 independent sources confirmed before publication. No speculation._