Bug 2541031 (CVE-2026-97989) - CVE-2026-97989 kernel: vduse: validate virtqueue alignment
Summary: CVE-2026-97989 kernel: vduse: validate virtqueue alignment
Keywords:
Status: NEW
Alias: CVE-2026-97989
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
low
low
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-09-25 10:44 UTC by OSIDB Bzimport
Modified: 2026-09-30 08:26 UTC (History)
17 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:


Attachments (Terms of Use)

Description OSIDB Bzimport 2026-09-25 10:44:39 UTC
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.


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