{"id":"CVE-2026-63905","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-63905","generatedAt":"2026-10-28T00:28:34.010Z","title":"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().","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nusbip: vudc: Fix use after free bug in vudc_remove due to race condition\n\nThis patch follows up Zheng Wang's 2023 report of a use-after-free in\nvudc_remove(). The original thread stalled on Shuah Khan's request for\nruntime testing of the unplug/unbind path. This patch supplies that\ntesting and keeps Zheng's original fix shape.\n\nIn vudc_probe(), v_init_timer() binds udc->tr_timer.timer to v_timer().\nusbip_sockfd_store() starts the timer via v_start_timer()/v_kick_timer().\nvudc_remove() can then free the containing struct vudc while the timer is\nstill pending or executing.\n\nKASAN confirms the race on an unpatched x86_64 QEMU guest with\nCONFIG_KASAN=y, CONFIG_USBIP_VUDC=y, CONFIG_USB_ZERO=y, and a tight loop\nthat repeatedly writes a socket fd to usbip_sockfd, closes the socket\npair, and unbinds/rebinds usbip-vudc.0:\n\n  BUG: KASAN: slab-use-after-free in __run_timer_base.part.0+0x8ba/0x8e0\n  Write of size 8 at addr ffff888001b80740 by task trigger_and_unb/239\n  Allocated by task 239:\n    vudc_probe+0x4d/0xaa0\n  Freed by task 239:\n    kfree+0x18f/0x520\n    device_release_driver_internal+0x388/0x540\n    unbind_store+0xd9/0x100\n\nThis lands in the timer core rather than v_timer() itself because the\nembedded timer_list is being walked after its containing struct vudc has\nalready been freed. The underlying lifetime bug is the same one Zheng\nreported.\n\nWith v_stop_timer() called from vudc_remove() and the timer deleted\nsynchronously, the same harness completed 5000 bind/unbind iterations\nwith no KASAN report.","published":"2026-07-19T16:17:08.000Z","lastModified":"2026-07-27T17:44:24.000Z","status":"Awaiting Analysis","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","cvss":null,"cwe":[],"affected":[],"epss":{"score":0.0022,"percentile":0.12381,"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/1036ac6148995feaf486014d32bf26bf993c06a9","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/207bf80362df3fce8ebc9723351dcb1bc6d9ed0f","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/61704e5cf9cd7464b510eb606e7e2978b1160a64","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/88d459e5b5a46da1ef9fd6f52d9439343edeec88","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/a0638db2340ee053ab0450656a763fd111475e54","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/d07ed707467ce05ea9c03412d0c5ee9d0fe386a6","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/d96209626a29ea64666be98c30b30ac82e5f1be6","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/dcc1c90b28b28b7c493547506297e78653f81952","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-63905","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."}