drm/nouveau/uvmm: fix premature region free on failed OP_UNMAP_SPARSE

{
  "id": "221af5fe6780a5ffb1891623aeb453d6ddab1961e084d039bc5a5542f860977a",
  "url": "https://osv.dev/vulnerability/CVE-2026-89801",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "drm/nouveau/uvmm: fix premature region free on failed OP_UNMAP_SPARSE",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: drm/nouveau/uvmm: fix premature region free on failed OP_UNMAP_SPARSE In nouveau_uvmm_bind_job_submit()'s OP_UNMAP_SPARSE arm, op->reg is set from nouveau_uvma_region_find(), which only looks the region up and takes no reference; a region's sole reference is its membership in uvmm->region_mt. Two failure paths leave op->reg set: the -ENOENT check when the region is busy, and the drm_gpuvm_sm_unmap_ops_create() failure. The sibling nouveau_uvmm_sm_unmap_prepare() failure just below clears op->reg; these two do not. unwind_continue steps back one op, so the failing op is skipped by the unwind loop and its op->reg stays set. nouveau_uvmm_bind_job_cleanup() then enters its if (op->reg) branch and calls nouveau_uvma_region_remove() and nouveau_uvma_region_put() on it, dropping the tree's sole reference and freeing a region this job never created. The comment above the cleanup loop documents the broken invariant: op->reg must be NULL on submit failure. This frees a live region on an unrelated failure, reachable single-job when drm_gpuvm_sm_unmap_ops_create() returns -ENOMEM; if another job owns the same region, its cleanup then removes and puts the freed region, a use-after-free. Clear op->reg on both failure paths.",
    "evidence": "osv:CVE-2026-89801",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
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        "prerequisites": [],
        "fixed_versions": [
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            "evidence": "/affected/1/ranges"
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            "value": "6.12.110",
            "evidence": "/affected/1/ranges"
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            "value": "6.18.51",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.2.5",
            "evidence": "/affected/1/ranges"
          }
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        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-89801",
      "aliases": [
        "CVE-2026-89801"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
        }
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              "type": "GIT",
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                  "fixed": "ba42d8a1c2c7629c61914df11a7d63ac77449ffb"
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              "type": "ECOSYSTEM",
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          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
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      ],
      "modified": "2026-10-28T02:30:52.612936068Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/24c25b182d17d1bdfde0088c96bdf6f93e8f46bc",
        "https://git.kernel.org/stable/c/4083d24c2636fde7b18076115af52820d203bc57",
        "https://git.kernel.org/stable/c/88114e3a96582882e63b2f73aa7a5a9cf0d5073c",
        "https://git.kernel.org/stable/c/ba42d8a1c2c7629c61914df11a7d63ac77449ffb",
        "https://git.kernel.org/stable/c/ccf930812f23b8259ef64fd3394d53b093e4651a",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89801.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-89801",
        "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/2026/89xxx/CVE-2026-89801.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-89801",
        "evidence": "/id"
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    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
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  "source_id": "core-osv",
  "document_id": 521452,
  "published_at": "2026-09-16T10:30:34.458+00:00"
}