{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-23461",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2026-23461"
  ],
  "published": "2026-04-03T15:24:34Z",
  "summary": "Bluetooth: L2CAP: Fix use-after-free in l2cap_unregister_user",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: Fix use-after-free in l2cap_unregister_user\n\nAfter commit ab4eedb790ca (\"Bluetooth: L2CAP: Fix corrupted list in\nhci_chan_del\"), l2cap_conn_del() uses conn->lock to protect access to\nconn->users. However, l2cap_register_user() and l2cap_unregister_user()\ndon't use conn->lock, creating a race condition where these functions can\naccess conn->users and conn->hchan concurrently with l2cap_conn_del().\n\nThis can lead to use-after-free and list corruption bugs, as reported\nby syzbot.\n\nFix this by changing l2cap_register_user() and l2cap_unregister_user()\nto use conn->lock instead of hci_dev_lock(), ensuring consistent locking\nfor the l2cap_conn structure.",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
    }
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  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-23461"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/11a87dd5df428a4b79a84d2790cac7f3c73f1f0d"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/c22a5e659959eb77c2fbb58a5adfaf3c3dab7abf"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/da3000cbe4851458a22be38bb18c0689c39fdd5f"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/71030f3b3015a412133a805ff47970cdcf30c2b8"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/752a6c9596dd25efd6978a73ff21f3b592668f4a"
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  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-05T13:16:28Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 8.8,
      "cvss_v3_severity": "High",
      "scenario": "AV:A - The vulnerable L2CAP/HIDP teardown path is reachable through Bluetooth ACL/L2CAP connection handling by a nearby Bluetooth peer. Bluetooth proximity is an adjacent-network attack surface rather than internet-routable network access.\nAC:L - This is a locking/race use-after-free where the attacker can repeatedly drive HIDP/L2CAP connection teardown and unregister paths through connection close/disconnect behavior. The race is not dependent on a rare configuration or a condition outside attacker influence.\nPR:N - Although the local HIDP management ioctl path is gated by init-namespace CAP_NET_ADMIN, an adjacent malicious Bluetooth HID peer can trigger teardown of an already established HIDP/L2CAP session without privileges on the victim system. Under the higher-severity reasonable Bluetooth-peer scenario, no victim-system privileges are required.\nUI:N - Once the HIDP/L2CAP session exists, triggering the vulnerable unregister/connection-delete race does not require a victim user to perform an action. The peer can cause disconnect/teardown behavior directly.\nS:U - The vulnerability corrupts kernel Bluetooth/L2CAP state within the same kernel security authority. It is not a VM escape, IOMMU bypass, or other scope-changing boundary crossing.\nC:H - The flaw is a kernel use-after-free/list corruption condition involving L2CAP connection/user objects and potentially freed HCI device memory. Kernel UAFs are defensibly treated as enabling high confidentiality impact through memory disclosure primitives.\nI:H - The same UAF/list corruption can be leveraged beyond a crash for heap manipulation and control-flow or data-structure corruption. Kernel memory corruption is therefore high integrity impact.\nA:H - Syzbot reports show KASAN use-after-free crashes in l2cap_unregister_user, and the bug can corrupt lists during connection teardown. A kernel crash/oops is high availability impact."
    }
  }
}