CVE-2026-89955 (GCVE-0-2026-89955)
Vulnerability from cvelistv5
Published
2026-09-16 10:32
Modified
2026-10-30 12:33
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: s390/vfio-ap: Fix NULL deref in status_show() during queue probe When vfio_ap_mdev_probe_queue() creates the sysfs attribute group, the queue's driver data has not yet been set. A concurrent read of the 'status' attribute can therefore call dev_get_drvdata() and get NULL, which is then passed directly to vfio_ap_mdev_for_queue() where q->apqn is unconditionally dereferenced, causing a NULL pointer dereference. Fix this by acquiring the update locks before calling sysfs_create_group(). The status_show() function acquires guests_lock before reading the driver data, so any concurrent read will block until after dev_set_drvdata() has been called and the update locks are released. As a bonus, the APQN no longer needs to be read from the queue struct after allocation — it can be read directly from apdev before allocation and stored in a local variable, which is then assigned to q->apqn once the allocation succeeds.
References
Impacted products
Vendor Product Version
Linux Linux Version: 260f3ea141382386e97611e7c2029bc013088ab1
Version: 260f3ea141382386e97611e7c2029bc013088ab1
Version: 260f3ea141382386e97611e7c2029bc013088ab1
Version: 260f3ea141382386e97611e7c2029bc013088ab1
Version: 260f3ea141382386e97611e7c2029bc013088ab1
Version: 260f3ea141382386e97611e7c2029bc013088ab1
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{
  "containers": {
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          "product": "Linux",
          "programFiles": [
            "drivers/s390/crypto/vfio_ap_ops.c"
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          "vendor": "Linux",
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              "version": "6.0"
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              "versionType": "semver"
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              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
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          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
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                  "versionEndExcluding": "6.1.191",
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                  "vulnerable": true
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              "negate": false,
              "operator": "OR"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ns390/vfio-ap: Fix NULL deref in status_show() during queue probe\n\nWhen vfio_ap_mdev_probe_queue() creates the sysfs attribute group,\nthe queue\u0027s driver data has not yet been set. A concurrent read of\nthe \u0027status\u0027 attribute can therefore call dev_get_drvdata() and\nget NULL, which is then passed directly to\nvfio_ap_mdev_for_queue() where q-\u003eapqn is unconditionally\ndereferenced, causing a NULL pointer dereference.\n\nFix this by acquiring the update locks before calling\nsysfs_create_group(). The status_show() function acquires\nguests_lock before reading the driver data, so any concurrent\nread will block until after dev_set_drvdata() has been called\nand the update locks are released.\n\nAs a bonus, the APQN no longer needs to be read from the queue\nstruct after allocation \u2014 it can be read directly from apdev\nbefore allocation and stored in a local variable, which is then\nassigned to q-\u003eapqn once the allocation succeeds."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-30T12:33:33.417Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/10606c9af18baed75cd180b96ee695441aa15134"
        },
        {
          "url": "https://git.kernel.org/stable/c/31fa0a8a3c337ed2d200166d6926ab23c14f8b2e"
        },
        {
          "url": "https://git.kernel.org/stable/c/e102ce0f4af99dff769a4b1b4daa4cc6bd5ad2d9"
        },
        {
          "url": "https://git.kernel.org/stable/c/69632952aca04caa71e49953b6949fc04e788e67"
        },
        {
          "url": "https://git.kernel.org/stable/c/7db2511fc601ca3a6e3fb1bdce02261c3c3167c3"
        },
        {
          "url": "https://git.kernel.org/stable/c/dd6f4ef6f8a37412909ad787c837332fb070159c"
        }
      ],
      "title": "s390/vfio-ap: Fix NULL deref in status_show() during queue probe",
      "x_generator": {
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-89955",
    "datePublished": "2026-09-16T10:32:39.064Z",
    "dateReserved": "2026-09-11T19:38:34.777Z",
    "dateUpdated": "2026-10-30T12:33:33.417Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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