xen-netback: reject zero-queue configuration from guest
A malicious or buggy Xen guest can write "0" to the xenbus key
"multi-queue-num-queues". The connect() function in the backend only
validates the upper bound (requested_num_queues > xenvif_max_queues)
but not zero, allowing requested_num_queues=0 to reach
vzalloc(array_size(0, sizeof(struct xenvif_queue))), which triggers
WARN_ON_ONCE(!size) in __vmalloc_node_range().
On systems with panic_on_warn=1, this allows a guest-to-host denial
of service.
The Xen network interface specification requires
the queue count to be "greater than zero".
Add a zero check to match the validation already present
in xen-blkback, which has included this
guard since its multi-queue support was added.
Analysis and contextual insights are available on OpenCVE Cloud.
No vendor fix or workaround currently provided.
Additional remediation guidance may be available on OpenCVE Cloud.
Tracking
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| Source | ID | Title |
|---|---|---|
Debian DLA |
DLA-4606-1 | linux security update |
Thu, 28 May 2026 14:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-20 |
Thu, 28 May 2026 12:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-1284 | |
| References |
|
Wed, 27 May 2026 17:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-20 |
Wed, 27 May 2026 14:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: xen-netback: reject zero-queue configuration from guest A malicious or buggy Xen guest can write "0" to the xenbus key "multi-queue-num-queues". The connect() function in the backend only validates the upper bound (requested_num_queues > xenvif_max_queues) but not zero, allowing requested_num_queues=0 to reach vzalloc(array_size(0, sizeof(struct xenvif_queue))), which triggers WARN_ON_ONCE(!size) in __vmalloc_node_range(). On systems with panic_on_warn=1, this allows a guest-to-host denial of service. The Xen network interface specification requires the queue count to be "greater than zero". Add a zero check to match the validation already present in xen-blkback, which has included this guard since its multi-queue support was added. | |
| Title | xen-netback: reject zero-queue configuration from guest | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
|
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-05-27T12:17:01.466Z
Reserved: 2026-05-13T15:03:33.083Z
Link: CVE-2026-45890
No data.
Status : Awaiting Analysis
Published: 2026-05-27T14:17:03.040
Modified: 2026-06-17T10:52:40.773
Link: CVE-2026-45890
OpenCVE Enrichment
Updated: 2026-05-28T16:00:14Z
Debian DLA