PT-2026-61351 · Linux · Linux

CVE-2026-64034 · Published 2026-07-19 · Updated 2026-07-19

NVD

CVSS v3.1

9.3

Critical

Base vector

AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

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().

Fix

Related Identifiers

CVE-2026-64034

Affected Products

Linux

References · 8

• https://nvd.nist.gov/vuln/detail/CVE-2026-64034 · Security Note
• https://git.kernel.org/stable/c/566f42fb67a7ebfed6650e407e5b72e6b3e83bf7 · Note
• https://git.kernel.org/stable/c/a201c66edf2ebc6cfdc3813a889ba20fecebfae3 · Note
• https://git.kernel.org/stable/c/3c4db56ccd13dd020fbf43afabaee74a40ec75e4 · Note
• https://git.kernel.org/stable/c/6180a06bbc99fd9114b8db4be6c4d46e40f046ef · Note
• https://git.kernel.org/stable/c/70ad2dff8d052a85dfef15715b531f38a29108cf · Note
• https://git.kernel.org/stable/c/09ec063d87c2dd3fa6f3561361a017bd882e9f37 · Note
• https://git.kernel.org/stable/c/35f0f0a2536a4d604b4dbad92c85c4a8fdebb870 · Note