{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "86956e70761b3292156d668e87126844334dd71b"
            },
            {
              "fixed": "eb6cc898501a004c0fa8aab951351d9c959b91cc"
            },
            {
              "fixed": "6a180adafc2a8a5fbe815985c71b2201e93ab5e1"
            },
            {
              "fixed": "fc069d00a0dbef40042fd681554d48dcd5a1d524"
            },
            {
              "fixed": "13bfc94eef389bd664ffc67b00184919902c938a"
            },
            {
              "fixed": "4400270ec0348d05dc0439d8f0130853ce7f9e20"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "5.15.0"
            },
            {
              "fixed": "6.6.157"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.110"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.51"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.2.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89960.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ns390/vfio-ap: fix stale pqap_hook pointer on error in vfio_ap_mdev_set_kvm()\n\nIn vfio_ap_mdev_set_kvm(), kvm-\u003earch.crypto.pqap_hook is set to\n\u0026matrix_mdev-\u003epqap_hook before the update locks are acquired and the\nmdev list is checked for a conflicting assignment. If another mdev is\nalready attached to the same KVM instance, the function returns -EPERM\nwithout restoring the hook pointer, leaving kvm-\u003earch.crypto.pqap_hook\npointing at the failing matrix_mdev instead of the mdev that legitimately\nowns the KVM.\n\nSince matrix_mdev-\u003ekvm is never set on this error path,\nvfio_ap_mdev_unset_kvm() will not clean up the hook when matrix_mdev\nis later closed. If matrix_mdev is subsequently freed, any PQAP\ninstruction executed by the guest will dereference the stale pointer\nthrough pqap_hook_rwsem, resulting in a use-after-free.\n\nSince kvm-\u003earch.crypto.pqap_hook is only set in the vfio_ap_mdev_set_kvm()\nfunction and is cleared in the vfio_ap_mdev_unset_kvm() function, a check\nfor 'kvm-\u003earch.crypto.pqap_hook != NULL' is all that is needed to determine\nwhether it belongs to another mdev. This will alleviate the need to iterate\nthe matrix_dev-\u003emdev_list list to see if the kvm object is assigned to\nanother mdev.This was introduced in v3 to alleviate the need to take the\nmdevs_lock while iterating the list; however, this did not prevent a\npotential race condition.\n\nThe pqap_hook_rwsem(write) is now performed inside\nget_update_locks_for_kvm(), which is updated to acquire\npqap_hook_rwsem(write) between kvm-\u003elock and mdevs_lock. This ordering\nis consistent with the PQAP intercept path, which acquires pqap_hook_rwsem\nin read mode while srcu is held under vcpu-\u003emutex, establishing the\ndependency: kvm-\u003elock -\u003e vcpu-\u003emutex -\u003e srcu -\u003e pqap_hook_rwsem(read).\n\nThe pqap_hook_rwsem is now released inside the\nrelease_update_locks_for_kvm(), which is updated to release\npqap_hook_rwsem(write) between mdevs_lock and kvm-\u003elock.\n\nAdditionally, kvm_put_kvm() in vfio_ap_mdev_unset_kvm() is moved\nafter release_update_locks_for_kvm(). Previously it was called while\nkvm-\u003elock was held; if it were ever the last reference, kvm_destroy_vm()\nwould run under kvm-\u003elock, which would deadlock.",
  "id": "CVE-2026-89960",
  "modified": "2026-09-18T03:30:37.140608340Z",
  "published": "2026-09-16T10:32:42.618Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/13bfc94eef389bd664ffc67b00184919902c938a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4400270ec0348d05dc0439d8f0130853ce7f9e20"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/6a180adafc2a8a5fbe815985c71b2201e93ab5e1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/eb6cc898501a004c0fa8aab951351d9c959b91cc"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/fc069d00a0dbef40042fd681554d48dcd5a1d524"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89960.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-89960"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "s390/vfio-ap: fix stale pqap_hook pointer on error in vfio_ap_mdev_set_kvm()"
}