Live › vulnerability › CVE-2026-98509
Go to dashboardWhen a virtio-gpu execbuffer ioctl fails argument validation after a poll event was reserved, the kernel never frees that event, so memory leaks permanently. The sources describe a memory leak found by fuzzing, not an attacker gaining code execution or data.
Summary written from the sources below. Check the originals before acting.
First seen by InfraStack 2026-10-23 21:57 UTC. All times on this page are UTC.
Systems running a Linux kernel with the virtio-gpu DRM driver loaded, typically virtual machines with virtio GPU devices. Exposure depends on userspace being able to issue DRM execbuffer ioctls, which usually means local processes with access to the DRM device node. Hosts without virtio-gpu can skip it.
No product ranges from the sources yet.
uname -r and compare against the fixed kernel builds in the upstream stable commit for drm/virtiolsmod | grep virtio_gpu to see whether the virtio-gpu driver is loaded at allEach row is the first time that source carried this signal. The analyst’s rows are its own findings.
In the Linux kernel, the following vulnerability has been resolved:
drm/virtio: fix memory leak of fence event on execbuffer failure
virtio_gpu_execbuffer_ioctl() reserves a DRM event with drm_event_reserve_init() when VIRTGPU_EXECBUF_RING_IDX selects a ring that userspace has enabled polling for. virtio_gpu_init_submit() does this before the BO handles, the command buffer, the syncobj arrays and the in-fence are processed, so every later error path runs with the event already pending, including plain argument validation failures such as an invalid bo_handle or an in-syncobj that carries no fence.
On those paths, virtio_gpu_cleanup_submit() drops the out-fence without cancelling the event. The fence is freed without ever having been emitted, taking the only driver-side pointer to the event with it. Closing the DRM file does not help. drm_events_release() unlinks pending events but deliberately leaves the freeing to the driver's later drm_send_event(), which never runs for an orphaned event, so the allocation is leaked permanently.
Found when fuzzing the virtio driver with Syzkaller:
BUG: memory leak
unreferenced object 0xffff88802c176e80 (size 96):
comm "syz.1.367", pid 10561, jiffies 4294960122
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
c8 6e 17 2c 80 88 ff ff 00 00 00 00 00 00 00 00 .n.,............
backtrace (crc e1973c6b):
kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline]
slab_post_alloc_hook mm/slub.c:4597 [inline]
slab_alloc_node mm/slub.c:4917 [inline]
__kmalloc_cache_noprof+0x49d/0x6f0 mm/slub.c:5485
_kmalloc_noprof include/linux/slab.h:988 [inline]
_kzalloc_noprof include/linux/slab.h:1309 [inline]
virtio_gpu_fence_event_create drivers/gpu/drm/virtio/virtgpu_submit.c:282 [inline]
virtio_gpu_init_submit drivers/gpu/drm/virtio/virtgpu_submit.c:398 [inline]
virtio_gpu_execbuffer_ioctl+0xbbf/0x1aa0 drivers/gpu/drm/virtio/virtgpu_submit.c:505
drm_ioctl_kernel+0x1f4/0x3e0 drivers/gpu/drm/drm_ioctl.c:817
drm_ioctl+0x5f4/0xc70 drivers/gpu/drm/drm_ioctl.c:914
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl fs/ioctl.c:583 [inline]
__x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x116/0x800 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Fix by cancelling and freeing the DRM event on the execbuffer error path before dropping the fence. Clear the fence's event pointer after cancellation so it does not retain a dangling pointer.
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