CVE-2026-93683: Dpdk: dpdk: guest-triggered out-of-bounds walk via vhost indirect descriptor length toctou
A flaw was found in the DPDK vhost library. When handling a virtio indirect descriptor table, the host reads the table length more than once from guest memory and can allocate a host copy before validating that length. A guest that changes the length between those reads, or that supplies an out-of-range next index on a small host copy in the vDPA relay path, can cause the host vhost process to walk past the validated mapping or heap copy. That can crash or disrupt the vhost process. Out-of-bounds bytes are consumed as descriptor fields for GPA translation and are not returned to the guest as payload. This is a residual issue in the non-contiguous indirect descriptor copy path introduced as part of the CVE-2018-1059 fix.
Affected Software
Event History
Frequently Asked Questions
What level of attacker access is required to trigger this issue?
An attacker needs control of a guest that can provide virtio indirect descriptor tables to the host's DPDK vhost library. Exploitation requires changing the descriptor-table length between host reads or supplying an out-of-range next index in the vDPA relay path.
What is the practical impact on the host?
The issue can cause the host vhost process to read beyond a validated mapping or heap copy, potentially crashing or disrupting that process. The affected out-of-bounds bytes are interpreted as descriptor fields for GPA translation rather than returned to the guest as payload.
Which code path is specifically identified as affected?
The residual issue is in the non-contiguous indirect descriptor copy path. The description also identifies the vDPA relay path as a case where an out-of-range next index on a small host copy can trigger the out-of-bounds walk.