{"api_version":"1","generated_at":"2026-10-29T14:01:14+00:00","cve":"CVE-2025-68372","urls":{"html":"https://cve.report/CVE-2025-68372","api":"https://cve.report/api/cve/CVE-2025-68372.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2025-68372","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2025-68372"},"summary":{"title":"nbd: defer config put in recv_work","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnbd: defer config put in recv_work\n\nThere is one uaf issue in recv_work when running NBD_CLEAR_SOCK and\nNBD_CMD_RECONFIGURE:\n  nbd_genl_connect     // conf_ref=2 (connect and recv_work A)\n  nbd_open\t       // conf_ref=3\n  recv_work A done     // conf_ref=2\n  NBD_CLEAR_SOCK       // conf_ref=1\n  nbd_genl_reconfigure // conf_ref=2 (trigger recv_work B)\n  close nbd\t       // conf_ref=1\n  recv_work B\n    config_put         // conf_ref=0\n    atomic_dec(&config->recv_threads); -> UAF\n\nOr only running NBD_CLEAR_SOCK:\n  nbd_genl_connect   // conf_ref=2\n  nbd_open \t     // conf_ref=3\n  NBD_CLEAR_SOCK     // conf_ref=2\n  close nbd\n    nbd_release\n      config_put     // conf_ref=1\n  recv_work\n    config_put \t     // conf_ref=0\n    atomic_dec(&config->recv_threads); -> UAF\n\nCommit 87aac3a80af5 (\"nbd: call nbd_config_put() before notifying the\nwaiter\") moved nbd_config_put() to run before waking up the waiter in\nrecv_work, in order to ensure that nbd_start_device_ioctl() would not\nbe woken up while nbd->task_recv was still uncleared.\n\nHowever, in nbd_start_device_ioctl(), after being woken up it explicitly\ncalls flush_workqueue() to make sure all current works are finished.\nTherefore, there is no need to move the config put ahead of the wakeup.\n\nMove nbd_config_put() to the end of recv_work, so that the reference is\nheld for the whole lifetime of the worker thread. This makes sure the\nconfig cannot be freed while recv_work is still running, even if clear\n+ reconfigure interleave.\n\nIn addition, we don't need to worry about recv_work dropping the last\nnbd_put (which causes deadlock):\n\npath A (netlink with NBD_CFLAG_DESTROY_ON_DISCONNECT):\n  connect  // nbd_refs=1 (trigger recv_work)\n  open nbd // nbd_refs=2\n  NBD_CLEAR_SOCK\n  close nbd\n    nbd_release\n      nbd_disconnect_and_put\n        flush_workqueue // recv_work done\n      nbd_config_put\n        nbd_put // nbd_refs=1\n      nbd_put // nbd_refs=0\n        queue_work\n\npath B (netlink without NBD_CFLAG_DESTROY_ON_DISCONNECT):\n  connect  // nbd_refs=2 (trigger recv_work)\n  open nbd // nbd_refs=3\n  NBD_CLEAR_SOCK // conf_refs=2\n  close nbd\n    nbd_release\n      nbd_config_put // conf_refs=1\n      nbd_put // nbd_refs=2\n  recv_work done // conf_refs=0, nbd_refs=1\n  rmmod // nbd_refs=0\n\nDepends-on: e2daec488c57 (\"nbd: Fix hungtask when nbd_config_put\")","state":"PUBLISHED","assigner":"Linux","published_at":"2025-12-24 11:16:00","updated_at":"2026-10-13 11:10:00"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/742012f6bf29553fdc460bf646a58df3a7b43d01","name":"https://git.kernel.org/stable/c/742012f6bf29553fdc460bf646a58df3a7b43d01","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/6b69593f72e1bfba6ca47ca8d9b619341fded7d6","name":"https://git.kernel.org/stable/c/6b69593f72e1bfba6ca47ca8d9b619341fded7d6","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/198aa230a6f8c1f6af7ed26b29180749c3e79e4d","name":"https://git.kernel.org/stable/c/198aa230a6f8c1f6af7ed26b29180749c3e79e4d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/d3ba312675911ff9e3fefefd551751e153a9f0a9","name":"https://git.kernel.org/stable/c/d3ba312675911ff9e3fefefd551751e153a9f0a9","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/3692884bd6187d89d41eef81e5a9724519fd01c1","name":"https://git.kernel.org/stable/c/3692884bd6187d89d41eef81e5a9724519fd01c1","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/1ba2ced2bbdf7e64a30c3e88c70ea8bc208d1509","name":"https://git.kernel.org/stable/c/1ba2ced2bbdf7e64a30c3e88c70ea8bc208d1509","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/443a1721806b6ff6303b5229e9811d68172d622f","name":"https://git.kernel.org/stable/c/443a1721806b6ff6303b5229e9811d68172d622f","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/9517b82d8d422d426a988b213fdd45c6b417b86d","name":"https://git.kernel.org/stable/c/9517b82d8d422d426a988b213fdd45c6b417b86d","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2025-68372","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2025-68372","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 87aac3a80af5cbad93e63250e8a1e19095ba0d30 198aa230a6f8c1f6af7ed26b29180749c3e79e4d git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 87aac3a80af5cbad93e63250e8a1e19095ba0d30 d3ba312675911ff9e3fefefd551751e153a9f0a9 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 87aac3a80af5cbad93e63250e8a1e19095ba0d30 3692884bd6187d89d41eef81e5a9724519fd01c1 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 87aac3a80af5cbad93e63250e8a1e19095ba0d30 1ba2ced2bbdf7e64a30c3e88c70ea8bc208d1509 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 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the Linux kernel, the following vulnerability has been resolved:\n\nnbd: defer config put in recv_work\n\nThere is one uaf issue in recv_work when running NBD_CLEAR_SOCK and\nNBD_CMD_RECONFIGURE:\n  nbd_genl_connect     // conf_ref=2 (connect and recv_work A)\n  nbd_open\t       // conf_ref=3\n  recv_work A done     // conf_ref=2\n  NBD_CLEAR_SOCK       // conf_ref=1\n  nbd_genl_reconfigure // conf_ref=2 (trigger recv_work B)\n  close nbd\t       // conf_ref=1\n  recv_work B\n    config_put         // conf_ref=0\n    atomic_dec(&config->recv_threads); -> UAF\n\nOr only running NBD_CLEAR_SOCK:\n  nbd_genl_connect   // conf_ref=2\n  nbd_open \t     // conf_ref=3\n  NBD_CLEAR_SOCK     // conf_ref=2\n  close nbd\n    nbd_release\n      config_put     // conf_ref=1\n  recv_work\n    config_put \t     // conf_ref=0\n    atomic_dec(&config->recv_threads); -> UAF\n\nCommit 87aac3a80af5 (\"nbd: call nbd_config_put() before notifying the\nwaiter\") moved nbd_config_put() to run before waking up the waiter in\nrecv_work, in order to ensure that nbd_start_device_ioctl() would not\nbe woken up while nbd->task_recv was still uncleared.\n\nHowever, in nbd_start_device_ioctl(), after being woken up it explicitly\ncalls flush_workqueue() to make sure all current works are finished.\nTherefore, there is no need to move the config put ahead of the wakeup.\n\nMove nbd_config_put() to the end of recv_work, so that the reference is\nheld for the whole lifetime of the worker thread. This makes sure the\nconfig cannot be freed while recv_work is still running, even if clear\n+ reconfigure interleave.\n\nIn addition, we don't need to worry about recv_work dropping the last\nnbd_put (which causes deadlock):\n\npath A (netlink with NBD_CFLAG_DESTROY_ON_DISCONNECT):\n  connect  // nbd_refs=1 (trigger recv_work)\n  open nbd // nbd_refs=2\n  NBD_CLEAR_SOCK\n  close nbd\n    nbd_release\n      nbd_disconnect_and_put\n        flush_workqueue // recv_work done\n      nbd_config_put\n        nbd_put // nbd_refs=1\n      nbd_put // nbd_refs=0\n        queue_work\n\npath B (netlink without NBD_CFLAG_DESTROY_ON_DISCONNECT):\n  connect  // nbd_refs=2 (trigger recv_work)\n  open nbd // nbd_refs=3\n  NBD_CLEAR_SOCK // conf_refs=2\n  close nbd\n    nbd_release\n      nbd_config_put // conf_refs=1\n      nbd_put // nbd_refs=2\n  recv_work done // conf_refs=0, nbd_refs=1\n  rmmod // nbd_refs=0\n\nDepends-on: e2daec488c57 (\"nbd: Fix hungtask when nbd_config_put\")"}],"providerMetadata":{"dateUpdated":"2026-05-23T16:02:46.914Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/198aa230a6f8c1f6af7ed26b29180749c3e79e4d"},{"url":"https://git.kernel.org/stable/c/d3ba312675911ff9e3fefefd551751e153a9f0a9"},{"url":"https://git.kernel.org/stable/c/3692884bd6187d89d41eef81e5a9724519fd01c1"},{"url":"https://git.kernel.org/stable/c/1ba2ced2bbdf7e64a30c3e88c70ea8bc208d1509"},{"url":"https://git.kernel.org/stable/c/6b69593f72e1bfba6ca47ca8d9b619341fded7d6"},{"url":"https://git.kernel.org/stable/c/443a1721806b6ff6303b5229e9811d68172d622f"},{"url":"https://git.kernel.org/stable/c/742012f6bf29553fdc460bf646a58df3a7b43d01"},{"url":"https://git.kernel.org/stable/c/9517b82d8d422d426a988b213fdd45c6b417b86d"}],"title":"nbd: defer config put in recv_work","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2025-68372","datePublished":"2025-12-24T10:33:02.679Z","dateReserved":"2025-12-16T14:48:05.310Z","dateUpdated":"2026-06-16T19:28:42.649Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2025-12-24 11:16:00","lastModifiedDate":"2026-10-13 11:10:00","problem_types":[],"metrics":{"ssvcV203":[{"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0","ssvcData":{"timestamp":"2026-06-16T19:28:28.671225Z","id":"CVE-2025-68372","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2025","CveId":"68372","Ordinal":"1","Title":"nbd: defer config put in recv_work","CVE":"CVE-2025-68372","Year":"2025"},"notes":[{"CveYear":"2025","CveId":"68372","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nnbd: defer config put in recv_work\n\nThere is one uaf issue in recv_work when running NBD_CLEAR_SOCK and\nNBD_CMD_RECONFIGURE:\n  nbd_genl_connect     // conf_ref=2 (connect and recv_work A)\n  nbd_open\t       // conf_ref=3\n  recv_work A done     // conf_ref=2\n  NBD_CLEAR_SOCK       // conf_ref=1\n  nbd_genl_reconfigure // conf_ref=2 (trigger recv_work B)\n  close nbd\t       // conf_ref=1\n  recv_work B\n    config_put         // conf_ref=0\n    atomic_dec(&config->recv_threads); -> UAF\n\nOr only running NBD_CLEAR_SOCK:\n  nbd_genl_connect   // conf_ref=2\n  nbd_open \t     // conf_ref=3\n  NBD_CLEAR_SOCK     // conf_ref=2\n  close nbd\n    nbd_release\n      config_put     // conf_ref=1\n  recv_work\n    config_put \t     // conf_ref=0\n    atomic_dec(&config->recv_threads); -> UAF\n\nCommit 87aac3a80af5 (\"nbd: call nbd_config_put() before notifying the\nwaiter\") moved nbd_config_put() to run before waking up the waiter in\nrecv_work, in order to ensure that nbd_start_device_ioctl() would not\nbe woken up while nbd->task_recv was still uncleared.\n\nHowever, in nbd_start_device_ioctl(), after being woken up it explicitly\ncalls flush_workqueue() to make sure all current works are finished.\nTherefore, there is no need to move the config put ahead of the wakeup.\n\nMove nbd_config_put() to the end of recv_work, so that the reference is\nheld for the whole lifetime of the worker thread. This makes sure the\nconfig cannot be freed while recv_work is still running, even if clear\n+ reconfigure interleave.\n\nIn addition, we don't need to worry about recv_work dropping the last\nnbd_put (which causes deadlock):\n\npath A (netlink with NBD_CFLAG_DESTROY_ON_DISCONNECT):\n  connect  // nbd_refs=1 (trigger recv_work)\n  open nbd // nbd_refs=2\n  NBD_CLEAR_SOCK\n  close nbd\n    nbd_release\n      nbd_disconnect_and_put\n        flush_workqueue // recv_work done\n      nbd_config_put\n        nbd_put // nbd_refs=1\n      nbd_put // nbd_refs=0\n        queue_work\n\npath B (netlink without NBD_CFLAG_DESTROY_ON_DISCONNECT):\n  connect  // nbd_refs=2 (trigger recv_work)\n  open nbd // nbd_refs=3\n  NBD_CLEAR_SOCK // conf_refs=2\n  close nbd\n    nbd_release\n      nbd_config_put // conf_refs=1\n      nbd_put // nbd_refs=2\n  recv_work done // conf_refs=0, nbd_refs=1\n  rmmod // nbd_refs=0\n\nDepends-on: e2daec488c57 (\"nbd: Fix hungtask when nbd_config_put\")","Type":"Description","Title":"nbd: defer config put in recv_work"}]}}}