{"id":"CVE-2026-80824","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-80824","generatedAt":"2026-10-28T03:30:00.428Z","title":"In the Linux kernel, the following vulnerability has been resolved: usb: usbfs: fix use-after-free of usb_device in usbdev_release() usbdev_release() drops its reference to the struct usb_device before draining the list of completed async URBs, but that…","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nusb: usbfs: fix use-after-free of usb_device in usbdev_release()\n\nusbdev_release() drops its reference to the struct usb_device before\ndraining the list of completed async URBs, but that drain path reads back\nthrough the same object: free_async() calls dec_usb_memory_use_count()\nfor any URB whose buffer came from the usbfs mmap() region, and its first\nstatement is bus_to_hcd(ps->dev->bus).\n\nAfter a disconnect the usbfs reference can be the last one, in which case\nusb_put_dev() frees the device and the subsequent loop reads offset 80 of\nfreed memory and uses the result as a struct usb_hcd *, which\nhcd_buffer_free_pages() then dereferences.\n\nThis is reachable by an unprivileged process that has read/write access to\na /dev/bus/usb node: mmap() the fd, submit one URB with a buffer inside the\nmapping, wait for the device to be unplugged, then munmap() and close().\nIt reproduces on every attempt rather than being a race, because a live\nMAP_SHARED vma holds a reference on the struct file, so usbdev_release()\ncannot run until the last vma is gone and the freeing branch of\ndec_usb_memory_use_count() is always taken.\n\n  BUG: KASAN: slab-use-after-free in dec_usb_memory_use_count+0x3ae/0x410\n  Read of size 8 at addr ffff8880122ee050 by task poc/769\n  CPU: 1 UID: 1000 PID: 769 Comm: poc Tainted: G    B    6.12.94 #3\n\n  Call Trace:\n   dec_usb_memory_use_count+0x3ae/0x410\n   free_async+0x2aa/0x4f0\n   usbdev_release+0x375/0x460\n   __fput+0x3ea/0xb50\n   __x64_sys_close+0x86/0x100\n\n  Allocated by task 11:\n   usb_alloc_dev+0x55/0xd90\n   hub_event+0x2524/0x43d0\n\n  Freed by task 769:\n   kfree+0x121/0x360\n   device_release+0xd2/0x280\n   usb_put_dev+0x23/0x30\n   usbdev_release+0x2d8/0x460\n\nRelease the device reference after the drain loop instead. Nothing between\nthe two points requires it to have been dropped.","published":"2026-09-04T16:18:10.000Z","lastModified":"2026-10-19T09:17:17.000Z","status":"Received","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","cvss":null,"cwe":[],"affected":[],"epss":{"score":0.00195,"percentile":0.09118,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"unknown","text":"Not yet scored. NVD analysis is pending; check back once CVSS and EPSS values are published."},"changes":[],"references":[{"url":"https://git.kernel.org/stable/c/0a960b88c5979f853019d4dc4957dfbeeb193440","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/0dd68b5d01d022fc9c5e71c82a82b0a94d3d0671","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/47a7f98fbb5006d46d15a3a210ffdc61448a4f19","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/5f08c45bdcfd28d1171de38c5ef29fc89a76eedc","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/65879e0a452ca2a234b9475e0c11aff7a4343738","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/7f0278e474c4d1c4457974ff1137cc385c944ab3","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/96f5520fc9a5e4bbf77ac93c9d5ce502f597e6cf","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/b3cde26a66b04f1d90ed0b675899c88b4e49d424","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/bd4bffc621a8cb2f4d9ed9b6447415de524a3bef","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-80824","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}