CVE-2026-22995 (GCVE-0-2026-22995)

Vulnerability from cvelistv5 – Published: 2026-01-23 15:24 – Updated: 2026-05-11 21:57
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
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 63dfbcd59b4b823eac4441efff10b1c303c8f49f , < 72e28774e9644c2bdbb4920842fbf77103a15a85 (git)
Affected: 7fc4da6a304bdcd3de14fc946dc2c19437a9cc5a , < f0d385f6689f37a2828c686fb279121df006b4cb (git)
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Linux Linux Affected: 6.18.4 , < 6.18.6 (semver)
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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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    "dateReserved": "2026-01-13T15:37:45.938Z",
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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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            "value": "Se ha resuelto la siguiente vulnerabilidad en el kernel de Linux:\n\nublk: corrige uso despu\u00e9s de liberaci\u00f3n en ublk_partition_scan_work\n\nExiste una condici\u00f3n de carrera entre el trabajo de escaneo de particiones as\u00edncrono y el desmontaje del dispositivo que puede llevar a un uso despu\u00e9s de liberaci\u00f3n de ub-\u0026gt;ub_disk:\n\n1. ublk_ctrl_start_dev() programa partition_scan_work despu\u00e9s de add_disk()\n2. ublk_stop_dev() llama a ublk_stop_dev_unlocked() que hace:\n   - del_gendisk(ub-\u0026gt;ub_disk)\n   - ublk_detach_disk() establece ub-\u0026gt;ub_disk = NULL\n   - put_disk() que puede liberar el disco\n3. El worker ublk_partition_scan_work() entonces desreferencia ub-\u0026gt;ub_disk llevando a UAF\n\nCorrige esto usando ublk_get_disk()/ublk_put_disk() en el worker para mantener una referencia al disco durante el escaneo de particiones. El spinlock en ublk_get_disk() se sincroniza con ublk_detach_disk() asegurando que el worker o bien obtiene una referencia v\u00e1lida o ve NULL y sale temprano.\n\nTambi\u00e9n cambia flush_work() a cancel_work_sync() para evitar ejecutar innecesariamente el trabajo de escaneo de particiones cuando el disco ya est\u00e1 desmontado."
          }
        ],
        "id": "CVE-2026-22995",
        "lastModified": "2026-06-17T10:20:40.373",
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}



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