CVE-2026-22995 (GCVE-0-2026-22995)
Vulnerability from cvelistv5 – Published: 2026-01-23 15:24 – Updated: 2026-01-23 15:24
VLAI?
Title
ublk: fix use-after-free in ublk_partition_scan_work
Summary
In the Linux kernel, the following vulnerability has been resolved:
ublk: fix use-after-free in ublk_partition_scan_work
A race condition exists between the async partition scan work and device
teardown that can lead to a use-after-free of ub->ub_disk:
1. ublk_ctrl_start_dev() schedules partition_scan_work after add_disk()
2. ublk_stop_dev() calls ublk_stop_dev_unlocked() which does:
- del_gendisk(ub->ub_disk)
- ublk_detach_disk() sets ub->ub_disk = NULL
- put_disk() which may free the disk
3. The worker ublk_partition_scan_work() then dereferences ub->ub_disk
leading to UAF
Fix this by using ublk_get_disk()/ublk_put_disk() in the worker to hold
a reference to the disk during the partition scan. The spinlock in
ublk_get_disk() synchronizes with ublk_detach_disk() ensuring the worker
either gets a valid reference or sees NULL and exits early.
Also change flush_work() to cancel_work_sync() to avoid running the
partition scan work unnecessarily when the disk is already detached.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
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"version": "6.18.6",
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nublk: fix use-after-free in ublk_partition_scan_work\n\nA race condition exists between the async partition scan work and device\nteardown that can lead to a use-after-free of ub-\u003eub_disk:\n\n1. ublk_ctrl_start_dev() schedules partition_scan_work after add_disk()\n2. ublk_stop_dev() calls ublk_stop_dev_unlocked() which does:\n - del_gendisk(ub-\u003eub_disk)\n - ublk_detach_disk() sets ub-\u003eub_disk = NULL\n - put_disk() which may free the disk\n3. The worker ublk_partition_scan_work() then dereferences ub-\u003eub_disk\n leading to UAF\n\nFix this by using ublk_get_disk()/ublk_put_disk() in the worker to hold\na reference to the disk during the partition scan. The spinlock in\nublk_get_disk() synchronizes with ublk_detach_disk() ensuring the worker\neither gets a valid reference or sees NULL and exits early.\n\nAlso change flush_work() to cancel_work_sync() to avoid running the\npartition scan work unnecessarily when the disk is already detached."
}
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"providerMetadata": {
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"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"url": "https://git.kernel.org/stable/c/72e28774e9644c2bdbb4920842fbf77103a15a85"
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{
"url": "https://git.kernel.org/stable/c/f0d385f6689f37a2828c686fb279121df006b4cb"
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],
"title": "ublk: fix use-after-free in ublk_partition_scan_work",
"x_generator": {
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"cveId": "CVE-2026-22995",
"datePublished": "2026-01-23T15:24:15.684Z",
"dateReserved": "2026-01-13T15:37:45.938Z",
"dateUpdated": "2026-01-23T15:24:15.684Z",
"state": "PUBLISHED"
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"nvd": "{\"cve\":{\"id\":\"CVE-2026-22995\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-01-23T16:15:55.603\",\"lastModified\":\"2026-01-26T15:03:33.357\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nublk: fix use-after-free in ublk_partition_scan_work\\n\\nA race condition exists between the async partition scan work and device\\nteardown that can lead to a use-after-free of ub-\u003eub_disk:\\n\\n1. ublk_ctrl_start_dev() schedules partition_scan_work after add_disk()\\n2. ublk_stop_dev() calls ublk_stop_dev_unlocked() which does:\\n - del_gendisk(ub-\u003eub_disk)\\n - ublk_detach_disk() sets ub-\u003eub_disk = NULL\\n - put_disk() which may free the disk\\n3. The worker ublk_partition_scan_work() then dereferences ub-\u003eub_disk\\n leading to UAF\\n\\nFix this by using ublk_get_disk()/ublk_put_disk() in the worker to hold\\na reference to the disk during the partition scan. The spinlock in\\nublk_get_disk() synchronizes with ublk_detach_disk() ensuring the worker\\neither gets a valid reference or sees NULL and exits early.\\n\\nAlso change flush_work() to cancel_work_sync() to avoid running the\\npartition scan work unnecessarily when the disk is already detached.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/72e28774e9644c2bdbb4920842fbf77103a15a85\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/f0d385f6689f37a2828c686fb279121df006b4cb\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
}
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
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- Confirmed: The vulnerability has been validated from an analyst's perspective.
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- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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