usb: usbfs: fix use-after-free of usb_device in usbdev_release()

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-80824
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-04 16:18:10 UTC
Updated2026-09-04 16:18:10 UTC
DescriptionIn 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 drain path reads back through the same object: free_async() calls dec_usb_memory_use_count() for any URB whose buffer came from the usbfs mmap() region, and its first statement is bus_to_hcd(ps->dev->bus). After a disconnect the usbfs reference can be the last one, in which case usb_put_dev() frees the device and the subsequent loop reads offset 80 of freed memory and uses the result as a struct usb_hcd *, which hcd_buffer_free_pages() then dereferences. This is reachable by an unprivileged process that has read/write access to a /dev/bus/usb node: mmap() the fd, submit one URB with a buffer inside the mapping, wait for the device to be unplugged, then munmap() and close(). It reproduces on every attempt rather than being a race, because a live MAP_SHARED vma holds a reference on the struct file, so usbdev_release() cannot run until the last vma is gone and the freeing branch of dec_usb_memory_use_count() is always taken. BUG: KASAN: slab-use-after-free in dec_usb_memory_use_count+0x3ae/0x410 Read of size 8 at addr ffff8880122ee050 by task poc/769 CPU: 1 UID: 1000 PID: 769 Comm: poc Tainted: G B 6.12.94 #3 Call Trace: dec_usb_memory_use_count+0x3ae/0x410 free_async+0x2aa/0x4f0 usbdev_release+0x375/0x460 __fput+0x3ea/0xb50 __x64_sys_close+0x86/0x100 Allocated by task 11: usb_alloc_dev+0x55/0xd90 hub_event+0x2524/0x43d0 Freed by task 769: kfree+0x121/0x360 device_release+0xd2/0x280 usb_put_dev+0x23/0x30 usbdev_release+0x2d8/0x460 Release the device reference after the drain loop instead. Nothing between the two points requires it to have been dropped.

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected f7d34b445abc00e979b7cf36b9580ac3d1a47cd8 0a960b88c5979f853019d4dc4957dfbeeb193440 git Not specified
CNA Linux Linux affected f7d34b445abc00e979b7cf36b9580ac3d1a47cd8 96f5520fc9a5e4bbf77ac93c9d5ce502f597e6cf git Not specified
CNA Linux Linux affected f7d34b445abc00e979b7cf36b9580ac3d1a47cd8 bd4bffc621a8cb2f4d9ed9b6447415de524a3bef git Not specified
CNA Linux Linux affected f7d34b445abc00e979b7cf36b9580ac3d1a47cd8 65879e0a452ca2a234b9475e0c11aff7a4343738 git Not specified
CNA Linux Linux affected f7d34b445abc00e979b7cf36b9580ac3d1a47cd8 b3cde26a66b04f1d90ed0b675899c88b4e49d424 git Not specified
CNA Linux Linux affected f7d34b445abc00e979b7cf36b9580ac3d1a47cd8 5f08c45bdcfd28d1171de38c5ef29fc89a76eedc git Not specified
CNA Linux Linux affected f7d34b445abc00e979b7cf36b9580ac3d1a47cd8 7f0278e474c4d1c4457974ff1137cc385c944ab3 git Not specified
CNA Linux Linux affected f7d34b445abc00e979b7cf36b9580ac3d1a47cd8 47a7f98fbb5006d46d15a3a210ffdc61448a4f19 git Not specified
CNA Linux Linux affected f7d34b445abc00e979b7cf36b9580ac3d1a47cd8 0dd68b5d01d022fc9c5e71c82a82b0a94d3d0671 git Not specified
CNA Linux Linux affected 4.6 Not specified
CNA Linux Linux unaffected 4.6 semver Not specified
CNA Linux Linux unaffected 5.10.269 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.220 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.187 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.156 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.108 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.49 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.13 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2.3 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/47a7f98fbb5006d46d15a3a210ffdc61448a4f19 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/bd4bffc621a8cb2f4d9ed9b6447415de524a3bef 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/7f0278e474c4d1c4457974ff1137cc385c944ab3 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/b3cde26a66b04f1d90ed0b675899c88b4e49d424 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/96f5520fc9a5e4bbf77ac93c9d5ce502f597e6cf 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/5f08c45bdcfd28d1171de38c5ef29fc89a76eedc 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/0a960b88c5979f853019d4dc4957dfbeeb193440 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/65879e0a452ca2a234b9475e0c11aff7a4343738 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/0dd68b5d01d022fc9c5e71c82a82b0a94d3d0671 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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