FKIE_CVE-2026-64457

Vulnerability from fkie_nvd - Published: 2026-07-25 10:17 - Updated: 2026-11-03 18:15
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: virtio_pci: fix vq info pointer lookup via wrong index Unbinding a virtio balloon device: echo virtio0 > /sys/bus/virtio/drivers/virtio_balloon/unbind triggers a NULL pointer dereference. The dmesg says: BUG: kernel NULL pointer dereference, address: 0000000000000008 [...] RIP: 0010:__list_del_entry_valid_or_report+0x5/0xf0 Call Trace: <TASK> vp_del_vqs+0x121/0x230 remove_common+0x135/0x150 virtballoon_remove+0xee/0x100 virtio_dev_remove+0x3b/0x80 device_release_driver_internal+0x187/0x2c0 unbind_store+0xb9/0xe0 kernfs_fop_write_iter.llvm.11660790530567441834+0xf6/0x180 vfs_write+0x2a9/0x3b0 ksys_write+0x5c/0xd0 do_syscall_64+0x54/0x230 entry_SYSCALL_64_after_hwframe+0x29/0x31 [...] </TASK> The virtio_balloon device registers 5 queues (inflate, deflate, stats, free_page, reporting) but only the first two are unconditional. The stats, free_page and reporting queues are each conditional on their respective feature bits. When any of these features are absent, the corresponding vqs_info entry has name == NULL, creating holes in the array. The root cause is an indexing mismatch introduced when vq info storage was changed to be passed as an argument. vp_find_vqs_msix() and vp_find_vqs_intx() store the info pointer at vp_dev->vqs[i], where 'i' is the caller's sparse array index. However, the virtqueue itself gets vq->index assigned from queue_idx, a dense index that skips NULL entries. When holes exist, 'i' and queue_idx diverge. Later, vp_del_vqs() looks up info via vp_dev->vqs[vq->index] using the dense index into the sparsely-populated array, and hits NULL. Fix this by storing info at vp_dev->vqs[queue_idx] instead of vp_dev->vqs[i], so the store index matches the lookup index (vq->index). Apply the fix to both the MSIX and INTX paths.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/075bc3c779e1ea7294afabdcb7e0a49536959b28
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/41e6dc1a10036c9f47057033f19af7e52ec464b6
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/64a4c0befa77bcc01076aec9f93863ffd4ed06b7
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/f7d380fb525c13bdd114369a1979c80c346e6abc
Impacted products
Vendor Product Version
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{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/virtio/virtio_pci_common.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "41e6dc1a10036c9f47057033f19af7e52ec464b6",
              "status": "affected",
              "version": "89a1c435aec269d109ed46ca7bbb10fa8edf7ace",
              "versionType": "git"
            },
            {
              "lessThan": "075bc3c779e1ea7294afabdcb7e0a49536959b28",
              "status": "affected",
              "version": "89a1c435aec269d109ed46ca7bbb10fa8edf7ace",
              "versionType": "git"
            },
            {
              "lessThan": "64a4c0befa77bcc01076aec9f93863ffd4ed06b7",
              "status": "affected",
              "version": "89a1c435aec269d109ed46ca7bbb10fa8edf7ace",
              "versionType": "git"
            },
            {
              "lessThan": "f7d380fb525c13bdd114369a1979c80c346e6abc",
              "status": "affected",
              "version": "89a1c435aec269d109ed46ca7bbb10fa8edf7ace",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/virtio/virtio_pci_common.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.11"
            },
            {
              "lessThan": "6.11",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.96",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.39",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvirtio_pci: fix vq info pointer lookup via wrong index\n\nUnbinding a virtio balloon device:\n\n    echo virtio0 \u003e /sys/bus/virtio/drivers/virtio_balloon/unbind\n\ntriggers a NULL pointer dereference. The dmesg says:\n\n    BUG: kernel NULL pointer dereference, address: 0000000000000008\n    [...]\n    RIP: 0010:__list_del_entry_valid_or_report+0x5/0xf0\n    Call Trace:\n    \u003cTASK\u003e\n    vp_del_vqs+0x121/0x230\n    remove_common+0x135/0x150\n    virtballoon_remove+0xee/0x100\n    virtio_dev_remove+0x3b/0x80\n    device_release_driver_internal+0x187/0x2c0\n    unbind_store+0xb9/0xe0\n    kernfs_fop_write_iter.llvm.11660790530567441834+0xf6/0x180\n    vfs_write+0x2a9/0x3b0\n    ksys_write+0x5c/0xd0\n    do_syscall_64+0x54/0x230\n    entry_SYSCALL_64_after_hwframe+0x29/0x31\n    [...]\n    \u003c/TASK\u003e\n\nThe virtio_balloon device registers 5 queues (inflate, deflate, stats,\nfree_page, reporting) but only the first two are unconditional. The\nstats, free_page and reporting queues are each conditional on their\nrespective feature bits. When any of these features are absent, the\ncorresponding vqs_info entry has name == NULL, creating holes in the\narray.\n\nThe root cause is an indexing mismatch introduced when vq info storage\nwas changed to be passed as an argument. vp_find_vqs_msix() and\nvp_find_vqs_intx() store the info pointer at vp_dev-\u003evqs[i], where \u0027i\u0027\nis the caller\u0027s sparse array index. However, the virtqueue itself gets\nvq-\u003eindex assigned from queue_idx, a dense index that skips NULL\nentries. When holes exist, \u0027i\u0027 and queue_idx diverge. Later,\nvp_del_vqs() looks up info via vp_dev-\u003evqs[vq-\u003eindex] using the dense\nindex into the sparsely-populated array, and hits NULL.\n\nFix this by storing info at vp_dev-\u003evqs[queue_idx] instead of\nvp_dev-\u003evqs[i], so the store index matches the lookup index\n(vq-\u003eindex). Apply the fix to both the MSIX and INTX paths."
    }
  ],
  "id": "CVE-2026-64457",
  "lastModified": "2026-11-03T18:15:39.353",
  "metrics": {},
  "published": "2026-07-25T10:17:30.830",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/075bc3c779e1ea7294afabdcb7e0a49536959b28"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/41e6dc1a10036c9f47057033f19af7e52ec464b6"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/64a4c0befa77bcc01076aec9f93863ffd4ed06b7"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/f7d380fb525c13bdd114369a1979c80c346e6abc"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}



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