{"id":"CVE-2026-97996","summary":"virtio: fix use-after-free in unregister_virtio_device()","details":"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-\u003edebugfs_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.","modified":"2026-09-26T03:48:41.608296250Z","published":"2026-09-25T10:23:26.913Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/97xxx/CVE-2026-97996.json"},"references":[{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"},{"type":"WEB","url":"https://git.kernel.org/stable/c/3f9a0fceb730f5107d52421ead5568eae25a0049"},{"type":"WEB","url":"https://git.kernel.org/stable/c/77dbd10a701a30fdfea5c3bb7a29163128f9a9c7"},{"type":"WEB","url":"https://git.kernel.org/stable/c/951cad50cba89e736afdee4a730e0e52f9245c9b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/caf042153016d651b55d0fb4a63cdf7d0d23dee2"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/97xxx/CVE-2026-97996.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-97996"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"96a8326d69fffd7e8c2eb737dc060d8009a33b39"},{"fixed":"951cad50cba89e736afdee4a730e0e52f9245c9b"},{"fixed":"77dbd10a701a30fdfea5c3bb7a29163128f9a9c7"},{"fixed":"caf042153016d651b55d0fb4a63cdf7d0d23dee2"},{"fixed":"3f9a0fceb730f5107d52421ead5568eae25a0049"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-97996.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"6.10.0"},{"fixed":"6.12.111"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.53"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.7"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-97996.json"}}],"schema_version":"1.9.0"}