Bluetooth: L2CAP: fix out-of-bounds write in l2cap_ecred_connect

{
  "id": "77e79e8435986886428108d1580c505c035fb1037e707aabf47bd08e80f884d1",
  "url": "https://osv.dev/vulnerability/CVE-2026-98107",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Bluetooth: L2CAP: fix out-of-bounds write in l2cap_ecred_connect",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: Bluetooth: L2CAP: fix out-of-bounds write in l2cap_ecred_connect l2cap_chan_connect() tries to ensure there are no more than L2CAP_ECRED_CONN_SCID_MAX pending ECRED channels, so they fit in the same L2CAP_ECRED_CONN_REQ that l2cap_ecred_connect() constructs. However, the check only counts deferred channels. If 6 L2CAP sockets are connected at the same time in order DDDDND (D=deferred, N=non-deferred), the last can bump the total to max+1. It results to one __le16 written out of bounds of the scid array, and an invalid ECRED_CONN_REQ being sent. Fix by leaving room for the non-deferred pending ECRED channels in the counting in l2cap_chan_connect(), so the limit can't be exceeded. Move counting under same critical section where the channel is added. Although race conditions involving this appear unreachable, it's easier to see. Also add WARN_ON_ONCE check in l2cap_ecred_defer_connect() to make this less brittle.",
    "evidence": "osv:CVE-2026-98107",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
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            "evidence": "/affected/1/ranges"
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            "evidence": "/affected/1/ranges"
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    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-98107",
      "aliases": [
        "CVE-2026-98107"
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            "ecosystem": "Linux"
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      ],
      "modified": "2026-10-28T02:30:50.913452028Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/56c2b5831d39dc84aad2573dc3e197af1a872a05",
        "https://git.kernel.org/stable/c/6da5c0331fc3ef0c7b8df8269523fc3b2cce1e65",
        "https://git.kernel.org/stable/c/ce0927eb3ee2939fab5ce3f9334bfd2fafb38481",
        "https://git.kernel.org/stable/c/df8c3af6132640da4788e96a02d653e642059803",
        "https://git.kernel.org/stable/c/fabc5e04f123225daf980d03f2c5a05e7f0f0a7f",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98107.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-98107",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
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        "value": "CVE-2026-98107",
        "evidence": "/id"
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    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 519530,
  "published_at": "2026-09-25T10:35:56.34+00:00"
}