FKIE_CVE-2026-43364

Vulnerability from fkie_nvd - Published: 2026-05-08 15:16 - Updated: 2026-05-15 16:14
Severity
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/25966fc097691e5c925ad080f64a2f19c5fd940aPatch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c28d945bfa92e15147e93b73f95345b9bec979b0Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/f13fe6794726755a43090cb680c4c58cea6aa5f1Patch
Impacted products
Vendor Product Version
linux linux_kernel *
linux linux_kernel *
linux linux_kernel 7.0
linux linux_kernel 7.0
linux linux_kernel 7.0
To clipboard 

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  "cveTags": [],
  "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."
    }
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  "id": "CVE-2026-43364",
  "lastModified": "2026-05-15T16:14:44.557",
  "metrics": {
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          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
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        "impactScore": 3.6,
        "source": "nvd@nist.gov",
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  "published": "2026-05-08T15:16:47.383",
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          "value": "CWE-476"
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      "source": "nvd@nist.gov",
      "type": "Primary"
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}


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