{
  "cveId": "CVE-2026-89955",
  "url": "https://patchblox.com/security/cve/CVE-2026-89955",
  "summary": "CVE-2026-89955 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-89955, released September 23, 2026. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "s390/vfio-ap: Fix NULL deref in status_show() during queue probe",
  "description": "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\u0027s driver data has not yet been set. A concurrent read of the \u0027status\u0027 attribute can therefore call dev_get_drvdata() and get NULL, which is then passed directly to vfio_ap_mdev_for_queue() where q-\u003Eapqn 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 \u2014 it can be read directly from apdev before allocation and stored in a local variable, which is then assigned to q-\u003Eapqn once the allocation succeeds.",
  "published": "2026-09-16T11:17:05Z",
  "severity": "Moderate",
  "cvss": 5.5,
  "epss": 0.00205,
  "epssPercentile": 0.10616,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "vendorAdvisory": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-89955",
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "6.12.111-1",
      "fix": "DEBIAN-CVE-2026-89955",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-89955",
      "released": "2026-09-23T19:19:02Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "7.2.6-1",
      "fix": "DEBIAN-CVE-2026-89955",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-89955",
      "released": "2026-09-23T19:19:02Z"
    },
    {
      "platform": "linux",
      "product": "linux-6.12",
      "release": "Debian 12.15 (bookworm)",
      "fixedVersion": "6.12.111-1~deb12u1",
      "fix": "DEBIAN-CVE-2026-89955",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-89955",
      "released": "2026-09-23T19:19:02Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T00:53:09Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}