CVE-2026-43364 (GCVE-0-2026-43364)

Vulnerability from cvelistv5 – Published: 2026-05-08 14:21 – Updated: 2026-05-08 14:21
VLAI?
Title
ublk: fix NULL pointer dereference in ublk_ctrl_set_size()
Summary
In the Linux kernel, the following vulnerability has been resolved: ublk: fix NULL pointer dereference in ublk_ctrl_set_size() ublk_ctrl_set_size() unconditionally dereferences ub->ub_disk via set_capacity_and_notify() without checking if it is NULL. ub->ub_disk is NULL before UBLK_CMD_START_DEV completes (it is only assigned in ublk_ctrl_start_dev()) and after UBLK_CMD_STOP_DEV runs (ublk_detach_disk() sets it to NULL). Since the UBLK_CMD_UPDATE_SIZE handler performs no state validation, a user can trigger a NULL pointer dereference by sending UPDATE_SIZE to a device that has been added but not yet started, or one that has been stopped. Fix this by checking ub->ub_disk under ub->mutex before dereferencing it, and returning -ENODEV if the disk is not available.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 98b995660bff011d8e00af03abd74ac7d1ac1390 , < f13fe6794726755a43090cb680c4c58cea6aa5f1 (git)
Affected: 98b995660bff011d8e00af03abd74ac7d1ac1390 , < c28d945bfa92e15147e93b73f95345b9bec979b0 (git)
Affected: 98b995660bff011d8e00af03abd74ac7d1ac1390 , < 25966fc097691e5c925ad080f64a2f19c5fd940a (git)
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    Linux Linux Affected: 6.16
Unaffected: 0 , < 6.16 (semver)
Unaffected: 6.18.20 , ≤ 6.18.* (semver)
Unaffected: 6.19.9 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
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{
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          "product": "Linux",
          "programFiles": [
            "drivers/block/ublk_drv.c"
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              "operator": "OR"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nublk: fix NULL pointer dereference in ublk_ctrl_set_size()\n\nublk_ctrl_set_size() unconditionally dereferences ub-\u003eub_disk via\nset_capacity_and_notify() without checking if it is NULL.\n\nub-\u003eub_disk is NULL before UBLK_CMD_START_DEV completes (it is only\nassigned in ublk_ctrl_start_dev()) and after UBLK_CMD_STOP_DEV runs\n(ublk_detach_disk() sets it to NULL). Since the UBLK_CMD_UPDATE_SIZE\nhandler performs no state validation, a user can trigger a NULL pointer\ndereference by sending UPDATE_SIZE to a device that has been added but\nnot yet started, or one that has been stopped.\n\nFix this by checking ub-\u003eub_disk under ub-\u003emutex before dereferencing\nit, and returning -ENODEV if the disk is not available."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-08T14:21:17.654Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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          "url": "https://git.kernel.org/stable/c/c28d945bfa92e15147e93b73f95345b9bec979b0"
        },
        {
          "url": "https://git.kernel.org/stable/c/25966fc097691e5c925ad080f64a2f19c5fd940a"
        }
      ],
      "title": "ublk: fix NULL pointer dereference in ublk_ctrl_set_size()",
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    "cveId": "CVE-2026-43364",
    "datePublished": "2026-05-08T14:21:17.654Z",
    "dateReserved": "2026-05-01T14:12:56.005Z",
    "dateUpdated": "2026-05-08T14:21:17.654Z",
    "state": "PUBLISHED"
  },
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      "date": "2026-05-09",
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  }
}


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • 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.



Detection rules are retrieved from Rulezet.