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CVE PROGRAM SOURCE RECORDUnscored

CVE-2026-63905

usbip: vudc: Fix use after free bug in vudc_remove due to race condition

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: usbip: vudc: Fix use after free bug in vudc_remove due to race condition This patch follows up Zheng Wang's 2023 report of a use-after-free in vudc_remove(). The original thread stalled on Shuah Khan's request for runtime testing of the unplug/unbind path. This patch supplies that testing and keeps Zheng's original fix shape. In vudc_probe(), v_init_timer() binds udc->tr_timer.timer to v_timer(). usbip_sockfd_store() starts the timer via v_start_timer()/v_kick_timer(). vudc_remove() can then free the containing struct vudc while the timer is still pending or executing. KASAN confirms the race on an unpatched x86_64 QEMU guest with CONFIG_KASAN=y, CONFIG_USBIP_VUDC=y, CONFIG_USB_ZERO=y, and a tight loop that repeatedly writes a socket fd to usbip_sockfd, closes the socket pair, and unbinds/rebinds usbip-vudc.0: BUG: KASAN: slab-use-after-free in __run_timer_base.part.0+0x8ba/0x8e0 Write of size 8 at addr ffff888001b80740 by task trigger_and_unb/239 Allocated by task 239: vudc_probe+0x4d/0xaa0 Freed by task 239: kfree+0x18f/0x520 device_release_driver_internal+0x388/0x540 unbind_store+0xd9/0x100 This lands in the timer core rather than v_timer() itself because the embedded timer_list is being walked after its containing struct vudc has already been freed. The underlying lifetime bug is the same one Zheng reported. With v_stop_timer() called from vudc_remove() and the timer deleted synchronously, the same harness completed 5000 bind/unbind iterations with no KASAN report.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • b6a0ca11186759ad7045d68a5447b1e89f658384 to < 61704e5cf9cd7464b510eb606e7e2978b1160a64affected
  • b6a0ca11186759ad7045d68a5447b1e89f658384 to < dcc1c90b28b28b7c493547506297e78653f81952affected
  • b6a0ca11186759ad7045d68a5447b1e89f658384 to < 1036ac6148995feaf486014d32bf26bf993c06a9affected
  • b6a0ca11186759ad7045d68a5447b1e89f658384 to < a0638db2340ee053ab0450656a763fd111475e54affected
  • b6a0ca11186759ad7045d68a5447b1e89f658384 to < d07ed707467ce05ea9c03412d0c5ee9d0fe386a6affected
  • b6a0ca11186759ad7045d68a5447b1e89f658384 to < 88d459e5b5a46da1ef9fd6f52d9439343edeec88affected
  • b6a0ca11186759ad7045d68a5447b1e89f658384 to < 207bf80362df3fce8ebc9723351dcb1bc6d9ed0faffected
  • b6a0ca11186759ad7045d68a5447b1e89f658384 to < d96209626a29ea64666be98c30b30ac82e5f1be6affected

Linux Linux

Default version status: affected

  • 4.7affected
  • 0 to < 4.7unaffected
  • 5.10.259 to ≤ 5.10.*unaffected
  • 5.15.210 to ≤ 5.15.*unaffected
  • 6.1.176 to ≤ 6.1.*unaffected
  • 6.6.143 to ≤ 6.6.*unaffected
  • 6.12.93 to ≤ 6.12.*unaffected
  • 6.18.35 to ≤ 6.18.*unaffected
  • 7.0.12 to ≤ 7.0.*unaffected
  • 7.1 to ≤ *unaffected

References