drm/virtio: fix memory leak of fence event on execbuffer failure

{
  "id": "711f11e5c4398f3d9130dc162d80e74ea5c6fb9424035151f4eca18504c46fa8",
  "url": "https://osv.dev/vulnerability/CVE-2026-98509",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "drm/virtio: fix memory leak of fence event on execbuffer failure",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: drm/virtio: fix memory leak of fence event on execbuffer failure virtio_gpu_execbuffer_ioctl() reserves a DRM event with drm_event_reserve_init() when VIRTGPU_EXECBUF_RING_IDX selects a ring that userspace has enabled polling for. virtio_gpu_init_submit() does this before the BO handles, the command buffer, the syncobj arrays and the in-fence are processed, so every later error path runs with the event already pending, including plain argument validation failures such as an invalid bo_handle or an in-syncobj that carries no fence. On those paths, virtio_gpu_cleanup_submit() drops the out-fence without cancelling the event. The fence is freed without ever having been emitted, taking the only driver-side pointer to the event with it. Closing the DRM file does not help. drm_events_release() unlinks pending events but deliberately leaves the freeing to the driver's later drm_send_event(), which never runs for an orphaned event, so the allocation is leaked permanently. Found when fuzzing the virtio driver with Syzkaller: BUG: memory leak unreferenced object 0xffff88802c176e80 (size 96): comm \"syz.1.367\", pid 10561, jiffies 4294960122 hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ c8 6e 17 2c 80 88 ff ff 00 00 00 00 00 00 00 00 .n.,............ backtrace (crc e1973c6b): kmemleak_alloc_recursive include/linux/kmemleak.h:44 [inline] slab_post_alloc_hook mm/slub.c:4597 [inl",
    "evidence": "osv:CVE-2026-98509",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
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            "value": "6.6.158",
            "evidence": "/affected/1/ranges"
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          {
            "value": "6.12.112",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.55",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.2.9",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
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    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-98509",
      "aliases": [
        "CVE-2026-98509"
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      "affected": [
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            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98509.json"
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              "type": "ECOSYSTEM",
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          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
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          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98509.json"
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      ],
      "modified": "2026-10-28T02:30:50.696436389Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/43bfe2b60c149bf6effda25f245a00509061fa15",
        "https://git.kernel.org/stable/c/4e333e2336138f4659b1d7a0371c499f80428612",
        "https://git.kernel.org/stable/c/8fa78900fd24247277c03dc7b8a2864cb12d4340",
        "https://git.kernel.org/stable/c/ae583668f16d41fcc1b54f45848c1b6ac1d6669a",
        "https://git.kernel.org/stable/c/b74aad23d99b279bb34d135795f39a6d8ecdc075",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98509.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-98509",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98509.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-98509",
        "evidence": "/id"
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    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 519425,
  "published_at": "2026-10-18T15:17:19.352+00:00"
}