CVE-2026-64034
In the Linux kernel, the following vulnerability has been resolved:
net: mana: Fix TOCTOU double-fetch of hwcmsgid from DMA buffer
In manahwcrxeventhandler(), resp->response.hwcmsgid is read from
DMA-coherent memory and bounds-checked, then manahwchandle_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 hwcmsgid exactly once using READ_ONCE() into a
stack-local variable in manahwcrxeventhandler(), and passing the
validated value as a parameter to manahwchandle_resp().
Package Versions Affected
Automatically patch vulnerabilities without upgrading
CVSS Version



Related Resources
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, https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64034.json, https://nvd.nist.gov/vuln/detail/CVE-2026-64034, https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git