{"id":"CVE-2026-97996","state":"PUBLISHED","title":"virtio: fix use-after-free in unregister_virtio_device()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nvirtio: fix use-after-free in unregister_virtio_device()\n\ndevice_unregister() is device_del() plus put_device(). When the caller\nholds no extra reference, that drops the last one and runs the release\ncallback, which for several transports frees the memory the embedded\nstruct virtio_device sits in. unregister_virtio_device() then calls\nvirtio_debug_device_exit(), which reads dev->debugfs_dir out of the freed\nobject.\n\nAffected transports are the ones whose release callback frees and whose\nremove path takes no reference: virtio_mmio, virtio_vdpa, virtio_uml,\nmlxbf-tmfifo and virtio_ccw. virtio_pci is unaffected because\nvirtio_pci_remove() brackets the call with get_device() and put_device().\n\nRemove the debugfs entries before the device can go away. They are only\naccessed through the protected debugfs interface, so\ndebugfs_remove_recursive() waits for in-progress file operations before\nreturning. Tearing them down while the device is still alive is therefore\nsafe.\n\nReproduced on User-Mode Linux with CONFIG_KASAN and CONFIG_VIRTIO_DEBUG\nby unbinding a virtio-uml device:\n\n  BUG: KASAN: slab-use-after-free in virtio_debug_device_exit+0x36/0x4d\n  Read of size 8 at addr 00000000616e0b10 by task init/1\n   __asan_report_load8_noabort\n   virtio_debug_device_exit+0x36/0x4d\n   unregister_virtio_device+0x48/0x75\n   virtio_uml_remove\n   platform_remove\n   device_release_driver_internal\n   unbind_store\n\n  Freed by task 1:\n   kfree\n   virtio_uml_release_dev\n   device_release\n   kobject_put\n   put_device\n   device_unregister\n\nWith this applied, the report is gone and unbind is clean.","publishedAt":"2026-09-25T10:23:26.913Z","updatedAt":"2026-10-19T09:12:03.153Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"96a8326d69fffd7e8c2eb737dc060d8009a33b39","status":"affected","lessThan":"951cad50cba89e736afdee4a730e0e52f9245c9b","versionType":"git"},{"version":"96a8326d69fffd7e8c2eb737dc060d8009a33b39","status":"affected","lessThan":"77dbd10a701a30fdfea5c3bb7a29163128f9a9c7","versionType":"git"},{"version":"96a8326d69fffd7e8c2eb737dc060d8009a33b39","status":"affected","lessThan":"caf042153016d651b55d0fb4a63cdf7d0d23dee2","versionType":"git"},{"version":"96a8326d69fffd7e8c2eb737dc060d8009a33b39","status":"affected","lessThan":"3f9a0fceb730f5107d52421ead5568eae25a0049","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/virtio/virtio.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.10","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.10","versionType":"semver"},{"version":"6.12.111","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.53","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.7","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/virtio/virtio.c"]}],"references":["https://git.kernel.org/stable/c/951cad50cba89e736afdee4a730e0e52f9245c9b","https://git.kernel.org/stable/c/77dbd10a701a30fdfea5c3bb7a29163128f9a9c7","https://git.kernel.org/stable/c/caf042153016d651b55d0fb4a63cdf7d0d23dee2","https://git.kernel.org/stable/c/3f9a0fceb730f5107d52421ead5568eae25a0049"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:43.249Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/97xxx/CVE-2026-97996.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-97996","state":"PUBLISHED","datePublished":"2026-09-25T10:23:26.913Z","dateUpdated":"2026-10-19T09:12:03.153Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-25T10:18:58.209Z"},"containers":{"cna":{"title":"virtio: fix use-after-free in unregister_virtio_device()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nvirtio: fix use-after-free in unregister_virtio_device()\n\ndevice_unregister() is device_del() plus put_device(). When the caller\nholds no extra reference, that drops the last one and runs the release\ncallback, which for several transports frees the memory the embedded\nstruct virtio_device sits in. unregister_virtio_device() then calls\nvirtio_debug_device_exit(), which reads dev->debugfs_dir out of the freed\nobject.\n\nAffected transports are the ones whose release callback frees and whose\nremove path takes no reference: virtio_mmio, virtio_vdpa, virtio_uml,\nmlxbf-tmfifo and virtio_ccw. virtio_pci is unaffected because\nvirtio_pci_remove() brackets the call with get_device() and put_device().\n\nRemove the debugfs entries before the device can go away. They are only\naccessed through the protected debugfs interface, so\ndebugfs_remove_recursive() waits for in-progress file operations before\nreturning. Tearing them down while the device is still alive is therefore\nsafe.\n\nReproduced on User-Mode Linux with CONFIG_KASAN and CONFIG_VIRTIO_DEBUG\nby unbinding a virtio-uml device:\n\n  BUG: KASAN: slab-use-after-free in virtio_debug_device_exit+0x36/0x4d\n  Read of size 8 at addr 00000000616e0b10 by task init/1\n   __asan_report_load8_noabort\n   virtio_debug_device_exit+0x36/0x4d\n   unregister_virtio_device+0x48/0x75\n   virtio_uml_remove\n   platform_remove\n   device_release_driver_internal\n   unbind_store\n\n  Freed by task 1:\n   kfree\n   virtio_uml_release_dev\n   device_release\n   kobject_put\n   put_device\n   device_unregister\n\nWith this applied, the report is gone and unbind is clean."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"96a8326d69fffd7e8c2eb737dc060d8009a33b39","status":"affected","lessThan":"951cad50cba89e736afdee4a730e0e52f9245c9b","versionType":"git"},{"version":"96a8326d69fffd7e8c2eb737dc060d8009a33b39","status":"affected","lessThan":"77dbd10a701a30fdfea5c3bb7a29163128f9a9c7","versionType":"git"},{"version":"96a8326d69fffd7e8c2eb737dc060d8009a33b39","status":"affected","lessThan":"caf042153016d651b55d0fb4a63cdf7d0d23dee2","versionType":"git"},{"version":"96a8326d69fffd7e8c2eb737dc060d8009a33b39","status":"affected","lessThan":"3f9a0fceb730f5107d52421ead5568eae25a0049","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/virtio/virtio.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.10","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.10","versionType":"semver"},{"version":"6.12.111","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.53","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2.7","status":"unaffected","lessThanOrEqual":"7.2.*","versionType":"semver"},{"version":"7.3","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/virtio/virtio.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/951cad50cba89e736afdee4a730e0e52f9245c9b"},{"url":"https://git.kernel.org/stable/c/77dbd10a701a30fdfea5c3bb7a29163128f9a9c7"},{"url":"https://git.kernel.org/stable/c/caf042153016d651b55d0fb4a63cdf7d0d23dee2"},{"url":"https://git.kernel.org/stable/c/3f9a0fceb730f5107d52421ead5568eae25a0049"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-19T09:12:03.153Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"6.12.111"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"6.18.53"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"7.2.7"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"7.3"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}