{"api_version":"1","generated_at":"2026-07-23T20:50:46+00:00","cve":"CVE-2026-63905","urls":{"html":"https://cve.report/CVE-2026-63905","api":"https://cve.report/api/cve/CVE-2026-63905.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-63905","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-63905"},"summary":{"title":"usbip: vudc: Fix use after free bug in vudc_remove due to race condition","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.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-07-19 16:17:08","updated_at":"2026-07-19 16:17:08"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/207bf80362df3fce8ebc9723351dcb1bc6d9ed0f","name":"https://git.kernel.org/stable/c/207bf80362df3fce8ebc9723351dcb1bc6d9ed0f","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/dcc1c90b28b28b7c493547506297e78653f81952","name":"https://git.kernel.org/stable/c/dcc1c90b28b28b7c493547506297e78653f81952","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/61704e5cf9cd7464b510eb606e7e2978b1160a64","name":"https://git.kernel.org/stable/c/61704e5cf9cd7464b510eb606e7e2978b1160a64","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/a0638db2340ee053ab0450656a763fd111475e54","name":"https://git.kernel.org/stable/c/a0638db2340ee053ab0450656a763fd111475e54","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/d96209626a29ea64666be98c30b30ac82e5f1be6","name":"https://git.kernel.org/stable/c/d96209626a29ea64666be98c30b30ac82e5f1be6","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/1036ac6148995feaf486014d32bf26bf993c06a9","name":"https://git.kernel.org/stable/c/1036ac6148995feaf486014d32bf26bf993c06a9","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/88d459e5b5a46da1ef9fd6f52d9439343edeec88","name":"https://git.kernel.org/stable/c/88d459e5b5a46da1ef9fd6f52d9439343edeec88","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/d07ed707467ce05ea9c03412d0c5ee9d0fe386a6","name":"https://git.kernel.org/stable/c/d07ed707467ce05ea9c03412d0c5ee9d0fe386a6","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-63905","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-63905","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected b6a0ca11186759ad7045d68a5447b1e89f658384 61704e5cf9cd7464b510eb606e7e2978b1160a64 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected b6a0ca11186759ad7045d68a5447b1e89f658384 dcc1c90b28b28b7c493547506297e78653f81952 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected b6a0ca11186759ad7045d68a5447b1e89f658384 1036ac6148995feaf486014d32bf26bf993c06a9 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected b6a0ca11186759ad7045d68a5447b1e89f658384 a0638db2340ee053ab0450656a763fd111475e54 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15.210 5.15.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.1.176 6.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.6.143 6.6.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.12.93 6.12.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.35 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0.12 7.0.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"63905","cve":"CVE-2026-63905","epss":"0.002100000","percentile":"0.113630000","score_date":"2026-07-20","updated_at":"2026-07-21 00:13:14"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["drivers/usb/usbip/vudc_dev.c","drivers/usb/usbip/vudc_transfer.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"61704e5cf9cd7464b510eb606e7e2978b1160a64","status":"affected","version":"b6a0ca11186759ad7045d68a5447b1e89f658384","versionType":"git"},{"lessThan":"dcc1c90b28b28b7c493547506297e78653f81952","status":"affected","version":"b6a0ca11186759ad7045d68a5447b1e89f658384","versionType":"git"},{"lessThan":"1036ac6148995feaf486014d32bf26bf993c06a9","status":"affected","version":"b6a0ca11186759ad7045d68a5447b1e89f658384","versionType":"git"},{"lessThan":"a0638db2340ee053ab0450656a763fd111475e54","status":"affected","version":"b6a0ca11186759ad7045d68a5447b1e89f658384","versionType":"git"},{"lessThan":"d07ed707467ce05ea9c03412d0c5ee9d0fe386a6","status":"affected","version":"b6a0ca11186759ad7045d68a5447b1e89f658384","versionType":"git"},{"lessThan":"88d459e5b5a46da1ef9fd6f52d9439343edeec88","status":"affected","version":"b6a0ca11186759ad7045d68a5447b1e89f658384","versionType":"git"},{"lessThan":"207bf80362df3fce8ebc9723351dcb1bc6d9ed0f","status":"affected","version":"b6a0ca11186759ad7045d68a5447b1e89f658384","versionType":"git"},{"lessThan":"d96209626a29ea64666be98c30b30ac82e5f1be6","status":"affected","version":"b6a0ca11186759ad7045d68a5447b1e89f658384","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["drivers/usb/usbip/vudc_dev.c","drivers/usb/usbip/vudc_transfer.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"4.7"},{"lessThan":"4.7","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"5.10.*","status":"unaffected","version":"5.10.259","versionType":"semver"},{"lessThanOrEqual":"5.15.*","status":"unaffected","version":"5.15.210","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.176","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.143","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.93","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.35","versionType":"semver"},{"lessThanOrEqual":"7.0.*","status":"unaffected","version":"7.0.12","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.1","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.10.259","versionStartIncluding":"4.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"5.15.210","versionStartIncluding":"4.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.1.176","versionStartIncluding":"4.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.6.143","versionStartIncluding":"4.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.12.93","versionStartIncluding":"4.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.35","versionStartIncluding":"4.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.0.12","versionStartIncluding":"4.7","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1","versionStartIncluding":"4.7","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"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."}],"providerMetadata":{"dateUpdated":"2026-07-19T14:55:12.270Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/61704e5cf9cd7464b510eb606e7e2978b1160a64"},{"url":"https://git.kernel.org/stable/c/dcc1c90b28b28b7c493547506297e78653f81952"},{"url":"https://git.kernel.org/stable/c/1036ac6148995feaf486014d32bf26bf993c06a9"},{"url":"https://git.kernel.org/stable/c/a0638db2340ee053ab0450656a763fd111475e54"},{"url":"https://git.kernel.org/stable/c/d07ed707467ce05ea9c03412d0c5ee9d0fe386a6"},{"url":"https://git.kernel.org/stable/c/88d459e5b5a46da1ef9fd6f52d9439343edeec88"},{"url":"https://git.kernel.org/stable/c/207bf80362df3fce8ebc9723351dcb1bc6d9ed0f"},{"url":"https://git.kernel.org/stable/c/d96209626a29ea64666be98c30b30ac82e5f1be6"}],"title":"usbip: vudc: Fix use after free bug in vudc_remove due to race condition","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-63905","datePublished":"2026-07-19T14:55:12.270Z","dateReserved":"2026-07-19T07:54:57.020Z","dateUpdated":"2026-07-19T14:55:12.270Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-07-19 16:17:08","lastModifiedDate":"2026-07-19 16:17:08","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"63905","Ordinal":"1","Title":"usbip: vudc: Fix use after free bug in vudc_remove due to race c","CVE":"CVE-2026-63905","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"63905","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"usbip: vudc: Fix use after free bug in vudc_remove due to race c"}]}}}