vduse: validate virtqueue alignment
vduse_validate_config() only checks the upper bound of vq_align. Invalid
values can therefore reach vring_create_virtqueue_map(). The split-ring
helpers use align - 1 as a bit mask, so the alignment must be a non-zero
power of two. A zero value makes vring_size() drop the descriptor and
available-ring part and vring_init() leave the used ring pointer NULL.
The VIRTIO spec requires the used ring to start at an address
aligned to at least 4 bytes. Reject values below VRING_USED_ALIGN_SIZE as
well as non-power-of-two values before they reach the virtio ring helpers.
Opening a virtio-net device created with vq_align=0 triggered:
BUG: KASAN: null-ptr-deref in virtqueue_kick_prepare_split+0xe3/0x100
Read of size 2 at addr 0000000000000000 by task systemd-network/1062
Call Trace (relevant frames):
dump_stack_lvl
print_report
kasan_report
__asan_load2
virtqueue_kick_prepare_split+0xe3/0x100
virtqueue_kick_prepare+0x40/0x60
try_fill_recv+0x857/0x1250
virtnet_open+0x189/0x460
__dev_open+0x225/0x390
__dev_change_flags+0x368/0x3b0
netif_change_flags+0x56/0xc0
do_setlink.isra.0+0x68c/0x1e30
Validate the value before it reaches the virtio ring helpers.
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Solution
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Workaround
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Fri, 25 Sep 2026 14:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-20 CWE-476 |
Fri, 25 Sep 2026 10:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: vduse: validate virtqueue alignment vduse_validate_config() only checks the upper bound of vq_align. Invalid values can therefore reach vring_create_virtqueue_map(). The split-ring helpers use align - 1 as a bit mask, so the alignment must be a non-zero power of two. A zero value makes vring_size() drop the descriptor and available-ring part and vring_init() leave the used ring pointer NULL. The VIRTIO spec requires the used ring to start at an address aligned to at least 4 bytes. Reject values below VRING_USED_ALIGN_SIZE as well as non-power-of-two values before they reach the virtio ring helpers. Opening a virtio-net device created with vq_align=0 triggered: BUG: KASAN: null-ptr-deref in virtqueue_kick_prepare_split+0xe3/0x100 Read of size 2 at addr 0000000000000000 by task systemd-network/1062 Call Trace (relevant frames): dump_stack_lvl print_report kasan_report __asan_load2 virtqueue_kick_prepare_split+0xe3/0x100 virtqueue_kick_prepare+0x40/0x60 try_fill_recv+0x857/0x1250 virtnet_open+0x189/0x460 __dev_open+0x225/0x390 __dev_change_flags+0x368/0x3b0 netif_change_flags+0x56/0xc0 do_setlink.isra.0+0x68c/0x1e30 Validate the value before it reaches the virtio ring helpers. | |
| Title | vduse: validate virtqueue alignment | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-09-25T10:23:22.620Z
Reserved: 2026-09-25T10:18:58.209Z
Link: CVE-2026-97989
Vulnrichment
No data.
NVD
Status : Received
Published: 2026-09-25T11:17:27.010
Modified: 2026-09-25T11:17:27.010
Link: CVE-2026-97989
Redhat
No data.
OpenCVE Enrichment
Updated: 2026-09-25T14:30:14Z