CVE-2026-93683
Description
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.
Statement
This Moderate flaw in the DPDK vhost library allows a malicious guest to cause a denial of service on the host vhost process. By manipulating the virtio indirect descriptor table length, a guest can trigger an out-of-bounds memory access, leading to a crash or disruption of the vhost process. This issue requires a compromised guest to exploit.
Mitigation
No runtime mitigation. QEMU indirect_desc=off does not help: libvhost honours VRING_DESC_F_INDIRECT anyway. Do not expose vhost-user to untrusted guests.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 6.4 | N/A | 6.4 |
| Attack Vector | Local | N/A | Local |
| Attack Complexity | High | N/A | High |
| Privileges Required | Low | N/A | Low |
| User Interaction | None | N/A | None |
| Scope | Changed | N/A | Changed |
| Confidentiality | Low | N/A | Low |
| Integrity Impact | None | N/A | None |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:H
cve.org: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:L/I:N/A:H
Acknowledgements
Red Hat would like to thank Naseeb Dangi (AOSP Lab @Nankai University) and Xiang Li (AOSP Lab @Nankai University) for reporting this issue.
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