skbuff: Fix a race between coalescing and releasing SKBs

{
  "id": "b8486be0307e862fd5bdcf2d1f0edd7876a8d10c0a64c930964450aa9a507173",
  "url": "https://osv.dev/vulnerability/CVE-2023-53186",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "skbuff: Fix a race between coalescing and releasing SKBs",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: skbuff: Fix a race between coalescing and releasing SKBs Commit 1effe8ca4e34 (\"skbuff: fix coalescing for page_pool fragment recycling\") allowed coalescing to proceed with non page pool page and page pool page when @from is cloned, i.e. to->pp_recycle --> false from->pp_recycle --> true skb_cloned(from) --> true However, it actually requires skb_cloned(@from) to hold true until coalescing finishes in this situation. If the other cloned SKB is released while the merging is in process, from_shinfo->nr_frags will be set to 0 toward the end of the function, causing the increment of frag page _refcount to be unexpectedly skipped resulting in inconsistent reference counts. Later when SKB(@to) is released, it frees the page directly even though the page pool page is still in use, leading to use-after-free or double-free errors. So it should be prohibited. The double-free error message below prompted us to investigate: BUG: Bad page state in process swapper/1 pfn:0e0d1 page:00000000c6548b28 refcount:-1 mapcount:0 mapping:0000000000000000 index:0x2 pfn:0xe0d1 flags: 0xfffffc0000000(node=0|zone=1|lastcpupid=0x1fffff) raw: 000fffffc0000000 0000000000000000 ffffffff00000101 0000000000000000 raw: 0000000000000002 0000000000000000 ffffffffffffffff 0000000000000000 page dumped because: nonzero _refcount CPU: 1 PID: 0 Comm: swapper/1 Tainted: G E 6.2.0+ Call Trace: dump_stack_lvl+0x32/0x50 bad_page+0x69/0xf0 free_pcp_prepare",
    "evidence": "osv:CVE-2023-53186",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.15.108",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.25",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.2.12",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2023-53186",
      "aliases": [
        "CVE-2023-53186"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
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              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                  "fixed": "906a6689bb0191ad2a44131a3377006aa098af59"
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                {
                  "fixed": "71850b5af92da21b4862a9bc55bda61091247d00"
                },
                {
                  "fixed": "5f692c992a3bb9a8018e3488098b401a4229e7ec"
                },
                {
                  "fixed": "0646dc31ca886693274df5749cd0c8c1eaaeb5ca"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-53186.json"
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        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.15.0"
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                {
                  "fixed": "5.15.108"
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            {
              "type": "ECOSYSTEM",
              "events": [
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                  "introduced": "5.16.0"
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                {
                  "fixed": "6.1.25"
                }
              ]
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            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.2.0"
                },
                {
                  "fixed": "6.2.12"
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          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-53186.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:51.071748250Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/0646dc31ca886693274df5749cd0c8c1eaaeb5ca",
        "https://git.kernel.org/stable/c/5f692c992a3bb9a8018e3488098b401a4229e7ec",
        "https://git.kernel.org/stable/c/71850b5af92da21b4862a9bc55bda61091247d00",
        "https://git.kernel.org/stable/c/906a6689bb0191ad2a44131a3377006aa098af59",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/53xxx/CVE-2023-53186.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2023-53186",
        "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/2023/53xxx/CVE-2023-53186.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2023-53186",
        "evidence": "/id"
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    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 519645,
  "published_at": "2025-09-15T14:04:38.954+00:00"
}