CVE-2025-68372 - Vulnerability Details

Vendors	Products
Linux	Linux Kernel

Link	Providers
https://git.kernel.org/stable/c/443a1721806b6ff6303b5229e9811d68172d622f
https://git.kernel.org/stable/c/6b69593f72e1bfba6ca47ca8d9b619341fded7d6
https://git.kernel.org/stable/c/742012f6bf29553fdc460bf646a58df3a7b43d01
https://git.kernel.org/stable/c/9517b82d8d422d426a988b213fdd45c6b417b86d

Type	Values Removed	Values Added
Description		In the Linux kernel, the following vulnerability has been resolved: nbd: defer config put in recv_work There is one uaf issue in recv_work when running NBD_CLEAR_SOCK and NBD_CMD_RECONFIGURE: nbd_genl_connect // conf_ref=2 (connect and recv_work A) nbd_open // conf_ref=3 recv_work A done // conf_ref=2 NBD_CLEAR_SOCK // conf_ref=1 nbd_genl_reconfigure // conf_ref=2 (trigger recv_work B) close nbd // conf_ref=1 recv_work B config_put // conf_ref=0 atomic_dec(&config->recv_threads); -> UAF Or only running NBD_CLEAR_SOCK: nbd_genl_connect // conf_ref=2 nbd_open // conf_ref=3 NBD_CLEAR_SOCK // conf_ref=2 close nbd nbd_release config_put // conf_ref=1 recv_work config_put // conf_ref=0 atomic_dec(&config->recv_threads); -> UAF Commit 87aac3a80af5 ("nbd: call nbd_config_put() before notifying the waiter") moved nbd_config_put() to run before waking up the waiter in recv_work, in order to ensure that nbd_start_device_ioctl() would not be woken up while nbd->task_recv was still uncleared. However, in nbd_start_device_ioctl(), after being woken up it explicitly calls flush_workqueue() to make sure all current works are finished. Therefore, there is no need to move the config put ahead of the wakeup. Move nbd_config_put() to the end of recv_work, so that the reference is held for the whole lifetime of the worker thread. This makes sure the config cannot be freed while recv_work is still running, even if clear + reconfigure interleave. In addition, we don't need to worry about recv_work dropping the last nbd_put (which causes deadlock): path A (netlink with NBD_CFLAG_DESTROY_ON_DISCONNECT): connect // nbd_refs=1 (trigger recv_work) open nbd // nbd_refs=2 NBD_CLEAR_SOCK close nbd nbd_release nbd_disconnect_and_put flush_workqueue // recv_work done nbd_config_put nbd_put // nbd_refs=1 nbd_put // nbd_refs=0 queue_work path B (netlink without NBD_CFLAG_DESTROY_ON_DISCONNECT): connect // nbd_refs=2 (trigger recv_work) open nbd // nbd_refs=3 NBD_CLEAR_SOCK // conf_refs=2 close nbd nbd_release nbd_config_put // conf_refs=1 nbd_put // nbd_refs=2 recv_work done // conf_refs=0, nbd_refs=1 rmmod // nbd_refs=0 Depends-on: e2daec488c57 ("nbd: Fix hungtask when nbd_config_put")
Title		nbd: defer config put in recv_work
First Time appeared		Linux Linux linux Kernel
CPEs		cpe:2.3:o:linux:linux_kernel::::::::
Vendors & Products		Linux Linux linux Kernel
References		https://git.kernel.org/stable/c/443a1721806b6ff6303b5229e9811d68172d622f https://git.kernel.org/stable/c/6b69593f72e1bfba6ca47ca8d9b619341fded7d6 https://git.kernel.org/stable/c/742012f6bf29553fdc460bf646a58df3a7b43d01 https://git.kernel.org/stable/c/9517b82d8d422d426a988b213fdd45c6b417b86d

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2025-68372", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-12-16T14:48:05.310Z", "datePublished": "2025-12-24T10:33:02.679Z", "dateUpdated": "2025-12-24T10:33:02.679Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2025-12-24T10:33:02.679Z"}, "descriptions": [{"lang": "en", "value": "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\")"}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/block/nbd.c"], "versions": [{"version": "87aac3a80af5cbad93e63250e8a1e19095ba0d30", "lessThan": "6b69593f72e1bfba6ca47ca8d9b619341fded7d6", "status": "affected", "versionType": "git"}, {"version": "87aac3a80af5cbad93e63250e8a1e19095ba0d30", "lessThan": "443a1721806b6ff6303b5229e9811d68172d622f", "status": "affected", "versionType": "git"}, {"version": "87aac3a80af5cbad93e63250e8a1e19095ba0d30", "lessThan": "742012f6bf29553fdc460bf646a58df3a7b43d01", "status": "affected", "versionType": "git"}, {"version": "87aac3a80af5cbad93e63250e8a1e19095ba0d30", "lessThan": "9517b82d8d422d426a988b213fdd45c6b417b86d", "status": "affected", "versionType": "git"}, {"version": "0a4e383fc3aa6540f804c4fd1184a96ae5de6ef8", "status": "affected", "versionType": "git"}, {"version": "2ef6f4bd60411934e3fc2715442c2afe70f84bf3", "status": "affected", "versionType": "git"}, {"version": "742fd49cf811ca164489e339b862e3fb8e240a73", "status": "affected", "versionType": "git"}, {"version": "14df8724aeeef338172e2a2d6efadc989921ca0f", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/block/nbd.c"], "versions": [{"version": "5.10", "status": "affected"}, {"version": "0", "lessThan": "5.10", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.63", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.17.13", "lessThanOrEqual": "6.17.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.2", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.19-rc1", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10", "versionEndExcluding": "6.12.63"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10", "versionEndExcluding": "6.17.13"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10", "versionEndExcluding": "6.18.2"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10", "versionEndExcluding": "6.19-rc1"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.14.204"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.19.155"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.4.75"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.9.5"}]}]}], "references": [{"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"}}}}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "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\")"}], "id": "CVE-2025-68372", "lastModified": "2025-12-24T11:16:00.777", "metrics": {}, "published": "2025-12-24T11:16:00.777", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/443a1721806b6ff6303b5229e9811d68172d622f"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/6b69593f72e1bfba6ca47ca8d9b619341fded7d6"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/742012f6bf29553fdc460bf646a58df3a7b43d01"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/9517b82d8d422d426a988b213fdd45c6b417b86d"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

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