virtio: fix use-after-free in unregister_virtio_device()
Summary
| CVE | CVE-2026-97996 |
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| State | PUBLISHED |
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| Assigner | Linux |
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| Source Priority | CVE Program / NVD first with legacy fallback |
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| Published | 2026-09-25 11:17:27 UTC |
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| Updated | 2026-09-25 11:17:27 UTC |
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| Description | In the Linux kernel, the following vulnerability has been resolved:
virtio: fix use-after-free in unregister_virtio_device()
device_unregister() is device_del() plus put_device(). When the caller
holds no extra reference, that drops the last one and runs the release
callback, which for several transports frees the memory the embedded
struct virtio_device sits in. unregister_virtio_device() then calls
virtio_debug_device_exit(), which reads dev->debugfs_dir out of the freed
object.
Affected transports are the ones whose release callback frees and whose
remove path takes no reference: virtio_mmio, virtio_vdpa, virtio_uml,
mlxbf-tmfifo and virtio_ccw. virtio_pci is unaffected because
virtio_pci_remove() brackets the call with get_device() and put_device().
Remove the debugfs entries before the device can go away. They are only
accessed through the protected debugfs interface, so
debugfs_remove_recursive() waits for in-progress file operations before
returning. Tearing them down while the device is still alive is therefore
safe.
Reproduced on User-Mode Linux with CONFIG_KASAN and CONFIG_VIRTIO_DEBUG
by unbinding a virtio-uml device:
BUG: KASAN: slab-use-after-free in virtio_debug_device_exit+0x36/0x4d
Read of size 8 at addr 00000000616e0b10 by task init/1
__asan_report_load8_noabort
virtio_debug_device_exit+0x36/0x4d
unregister_virtio_device+0x48/0x75
virtio_uml_remove
platform_remove
device_release_driver_internal
unbind_store
Freed by task 1:
kfree
virtio_uml_release_dev
device_release
kobject_put
put_device
device_unregister
With this applied, the report is gone and unbind is clean. |
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Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|
| CNA |
Linux |
Linux |
affected 96a8326d69fffd7e8c2eb737dc060d8009a33b39 951cad50cba89e736afdee4a730e0e52f9245c9b git |
Not specified |
| CNA |
Linux |
Linux |
affected 96a8326d69fffd7e8c2eb737dc060d8009a33b39 77dbd10a701a30fdfea5c3bb7a29163128f9a9c7 git |
Not specified |
| CNA |
Linux |
Linux |
affected 96a8326d69fffd7e8c2eb737dc060d8009a33b39 caf042153016d651b55d0fb4a63cdf7d0d23dee2 git |
Not specified |
| CNA |
Linux |
Linux |
affected 96a8326d69fffd7e8c2eb737dc060d8009a33b39 3f9a0fceb730f5107d52421ead5568eae25a0049 git |
Not specified |
| CNA |
Linux |
Linux |
affected 6.10 |
Not specified |
| CNA |
Linux |
Linux |
unaffected 6.10 semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 6.12.111 6.12.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 6.18.53 6.18.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 7.2.7 7.2.* semver |
Not specified |
| CNA |
Linux |
Linux |
unaffected 7.3-rc3 * original_commit_for_fix |
Not specified |
References
| Reference | Source | Link | Tags |
|---|
| git.kernel.org/stable/c/77dbd10a701a30fdfea5c3bb7a29163128f9a9c7 |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/951cad50cba89e736afdee4a730e0e52f9245c9b |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/3f9a0fceb730f5107d52421ead5568eae25a0049 |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| git.kernel.org/stable/c/caf042153016d651b55d0fb4a63cdf7d0d23dee2 |
416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
git.kernel.org |
|
| CVE Program record |
CVE.ORG |
www.cve.org |
canonical |
| NVD vulnerability detail |
NVD |
nvd.nist.gov |
canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.