CVE-2026-97989 vduse: validate virtqueue alignment
A missing validation in the Linux kernel's vduse driver allows a local attacker to trigger a null pointer dereference and system crash by configuring invalid virtqueue alignment.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-97989?
CVE-2026-97989 is a vulnerability in Linux, published on 25 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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.
Which versions are affected by CVE-2026-97989?
How do I fix CVE-2026-97989?
Apply the vendor's patch.
Is CVE-2026-97989 being exploited?
There is no known exploitation of CVE-2026-97989 in the wild and no public exploit code.
Sources
Also known as AZL-104751, BELL-CVE-2026-97989, DEBIAN-CVE-2026-97989, GHSA-fgw5-49qv-38cm, UBUNTU-CVE-2026-97989.