CVE-2026-63905

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.
Configurations

Configuration 1 (hide)

OR cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc5:*:*:*:*:*:*

History

30 Oct 2026, 14:37

Type Values Removed Values Added
References () https://git.kernel.org/stable/c/1036ac6148995feaf486014d32bf26bf993c06a9 - () https://git.kernel.org/stable/c/1036ac6148995feaf486014d32bf26bf993c06a9 - Patch
References () https://git.kernel.org/stable/c/207bf80362df3fce8ebc9723351dcb1bc6d9ed0f - () https://git.kernel.org/stable/c/207bf80362df3fce8ebc9723351dcb1bc6d9ed0f - Patch
References () https://git.kernel.org/stable/c/61704e5cf9cd7464b510eb606e7e2978b1160a64 - () https://git.kernel.org/stable/c/61704e5cf9cd7464b510eb606e7e2978b1160a64 - Patch
References () https://git.kernel.org/stable/c/88d459e5b5a46da1ef9fd6f52d9439343edeec88 - () https://git.kernel.org/stable/c/88d459e5b5a46da1ef9fd6f52d9439343edeec88 - Patch
References () https://git.kernel.org/stable/c/a0638db2340ee053ab0450656a763fd111475e54 - () https://git.kernel.org/stable/c/a0638db2340ee053ab0450656a763fd111475e54 - Patch
References () https://git.kernel.org/stable/c/d07ed707467ce05ea9c03412d0c5ee9d0fe386a6 - () https://git.kernel.org/stable/c/d07ed707467ce05ea9c03412d0c5ee9d0fe386a6 - Patch
References () https://git.kernel.org/stable/c/d96209626a29ea64666be98c30b30ac82e5f1be6 - () https://git.kernel.org/stable/c/d96209626a29ea64666be98c30b30ac82e5f1be6 - Patch
References () https://git.kernel.org/stable/c/dcc1c90b28b28b7c493547506297e78653f81952 - () https://git.kernel.org/stable/c/dcc1c90b28b28b7c493547506297e78653f81952 - Patch
CWE CWE-416
CVSS v2 : unknown
v3 : unknown
v2 : unknown
v3 : 7.8
First Time Linux linux Kernel
Linux
CPE cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:*

Information

Published : 2026-07-19 16:17

Updated : 2026-10-30 14:37


NVD link : CVE-2026-63905

Mitre link : CVE-2026-63905

CVE.ORG link : CVE-2026-63905


JSON object : View

Products Affected

linux

  • linux_kernel
CWE
CWE-416

Use After Free