CVE-2025-68372 (GCVE-0-2025-68372)
Vulnerability from cvelistv5
Published
2025-12-24 10:33
Modified
2025-12-24 10:33
Severity ?
VLAI Severity ?
EPSS score ?
Summary
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")
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: 87aac3a80af5cbad93e63250e8a1e19095ba0d30 Version: 87aac3a80af5cbad93e63250e8a1e19095ba0d30 Version: 87aac3a80af5cbad93e63250e8a1e19095ba0d30 Version: 87aac3a80af5cbad93e63250e8a1e19095ba0d30 Version: 0a4e383fc3aa6540f804c4fd1184a96ae5de6ef8 Version: 2ef6f4bd60411934e3fc2715442c2afe70f84bf3 Version: 742fd49cf811ca164489e339b862e3fb8e240a73 Version: 14df8724aeeef338172e2a2d6efadc989921ca0f |
||
{
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"versionType": "original_commit_for_fix"
}
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}
],
"cpeApplicability": [
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"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(\u0026config-\u003erecv_threads); -\u003e 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(\u0026config-\u003erecv_threads); -\u003e 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-\u003etask_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\u0027t 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": "2025-12-24T10:33:02.679Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"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": {
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}
},
"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": "2025-12-24T10:33:02.679Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"nvd": "{\"cve\":{\"id\":\"CVE-2025-68372\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2025-12-24T11:16:00.777\",\"lastModified\":\"2025-12-24T11:16:00.777\",\"vulnStatus\":\"Received\",\"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(\u0026config-\u003erecv_threads); -\u003e 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(\u0026config-\u003erecv_threads); -\u003e 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-\u003etask_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\u0027t 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\\\")\"}],\"metrics\":{},\"references\":[{\"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\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
}
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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