nitro_enclaves: fix use-after-free on SLOT_ALLOC failure

{
  "id": "e13736ba151202f461fd99569b4cf6267b30b828676fdef3603c59f5824a51ff",
  "url": "https://osv.dev/vulnerability/CVE-2026-98775",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "nitro_enclaves: fix use-after-free on SLOT_ALLOC failure",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: nitro_enclaves: fix use-after-free on SLOT_ALLOC failure When ne_create_vm_ioctl() fails the SLOT_ALLOC request after anon_inode_getfile() has succeeded, the error path calls fput(enclave_file) and then frees ne_enclave. In normal userspace context, fput() defers the final __fput() via task_work. ne_enclave_release() therefore runs after ne_enclave has already been freed and dereferences ne_enclave->slot_uid, causing a use-after-free: KASAN: slab-use-after-free in ne_enclave_release. The enclave has no slot allocated and is not yet linked into the enclaves list on this error path, so ne_enclave_release() is expected to return early when slot_uid is zero. However, reading slot_uid already accesses the freed object. Clear enclave_file->private_data before fput() on the error path. ne_enclave_release() then returns immediately when private_data is NULL, leaving the ioctl error path as the sole owner of ne_enclave. This is safe because the file has not been fd_install()'d yet. Tested on an AWS EC2 m5.2xlarge with CONFIG_KASAN=y. Without the patch, the reproducer triggers a KASAN slab-use-after-free on every SLOT_ALLOC failure. With the patch, no KASAN report is produced and the SLOT_ALLOC error is still returned. Normal enclave creation and teardown are unaffected.",
    "evidence": "osv:CVE-2026-98775",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
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            "value": "5.10.273",
            "evidence": "/affected/1/ranges"
          },
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            "value": "5.15.224",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.191",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.160",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.113",
            "evidence": "/affected/1/ranges"
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          {
            "value": "6.18.56",
            "evidence": "/affected/1/ranges"
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          {
            "value": "7.2.10",
            "evidence": "/affected/1/ranges"
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        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-98775",
      "aliases": [
        "CVE-2026-98775"
      ],
      "affected": [
        {
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              "type": "GIT",
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                {
                  "fixed": "dac89ed976d9826eae4703281d0d51b062b58eef"
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                {
                  "fixed": "8024c50b8763add7912b6d9830327ba73f994204"
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                {
                  "fixed": "8bde6f643ab6fe5e3e3f4c312f84ce327ecf39b2"
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              "type": "ECOSYSTEM",
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                  "introduced": "5.10.0"
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                {
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            "ecosystem": "Linux"
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          "database_specific": {
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        }
      ],
      "modified": "2026-11-01T02:30:43.203172105Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/43f78b328f3907ca2f7424e15b7e45ffbf9fe21c",
        "https://git.kernel.org/stable/c/466041d14f26dc2babd606a2e85dce08774112a6",
        "https://git.kernel.org/stable/c/718965a5fcea47f7ec6accff55306317aadc3af3",
        "https://git.kernel.org/stable/c/8024c50b8763add7912b6d9830327ba73f994204",
        "https://git.kernel.org/stable/c/8bde6f643ab6fe5e3e3f4c312f84ce327ecf39b2",
        "https://git.kernel.org/stable/c/9bc184a2eda8b773c88ecbff934001ad649b9cc1",
        "https://git.kernel.org/stable/c/dac89ed976d9826eae4703281d0d51b062b58eef",
        "https://git.kernel.org/stable/c/f7fb6c2835ede1b8ad84cf7e78a528a9d0159b84",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98775.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-98775",
        "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-2026-98775.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-98775",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 507211,
  "published_at": "2026-10-18T15:48:11.317+00:00"
}