GHSA-6G4J-4JRG-PGPX

Vulnerability from github – Published: 2026-05-28 12:30 – Updated: 2026-05-28 12:30
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: virtio_bt: validate rx pkt_type header length

virtbt_rx_handle() reads the leading pkt_type byte from the RX skb and forwards the remainder to hci_recv_frame() for every event/ACL/SCO/ISO type, without checking that the remaining payload is at least the fixed HCI header for that type.

After the preceding patch bounds the backend-supplied used.len to [1, VIRTBT_RX_BUF_SIZE], a one-byte completion still reaches hci_recv_frame() with skb->len already pulled to 0. If the byte happened to be HCI_ACLDATA_PKT, the ACL-vs-ISO classification fast-path in hci_dev_classify_pkt_type() dereferences hci_acl_hdr(skb)->handle whenever the HCI device has an active CIS_LINK, BIS_LINK, or PA_LINK connection, reading two bytes of uninitialized RX-buffer data. The same hazard exists for every packet type the driver accepts because none of the switch cases in virtbt_rx_handle() check skb->len against the per-type minimum HCI header size before handing the frame to the core.

After stripping pkt_type, require skb->len to cover the fixed header size for the selected type (event 2, ACL 4, SCO 3, ISO 4) before calling hci_recv_frame(); drop ratelimited otherwise. Unknown pkt_type values still take the original kfree_skb() default path.

Use bt_dev_err_ratelimited() because both the length and pkt_type values come from an untrusted backend that can otherwise flood the kernel log.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-46186"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-05-28T10:16:34Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: virtio_bt: validate rx pkt_type header length\n\nvirtbt_rx_handle() reads the leading pkt_type byte from the RX skb\nand forwards the remainder to hci_recv_frame() for every\nevent/ACL/SCO/ISO type, without checking that the remaining payload\nis at least the fixed HCI header for that type.\n\nAfter the preceding patch bounds the backend-supplied used.len to\n[1, VIRTBT_RX_BUF_SIZE], a one-byte completion still reaches\nhci_recv_frame() with skb-\u003elen already pulled to 0. If the byte\nhappened to be HCI_ACLDATA_PKT, the ACL-vs-ISO classification\nfast-path in hci_dev_classify_pkt_type() dereferences\nhci_acl_hdr(skb)-\u003ehandle whenever the HCI device has an active\nCIS_LINK, BIS_LINK, or PA_LINK connection, reading two bytes of\nuninitialized RX-buffer data. The same hazard exists for every\npacket type the driver accepts because none of the switch cases in\nvirtbt_rx_handle() check skb-\u003elen against the per-type minimum HCI\nheader size before handing the frame to the core.\n\nAfter stripping pkt_type, require skb-\u003elen to cover the fixed\nheader size for the selected type (event 2, ACL 4, SCO 3, ISO 4)\nbefore calling hci_recv_frame(); drop ratelimited otherwise.\nUnknown pkt_type values still take the original kfree_skb() default\npath.\n\nUse bt_dev_err_ratelimited() because both the length and pkt_type\nvalues come from an untrusted backend that can otherwise flood the\nkernel log.",
  "id": "GHSA-6g4j-4jrg-pgpx",
  "modified": "2026-05-28T12:30:32Z",
  "published": "2026-05-28T12:30:32Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-46186"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1e1e509b6fd2a42421745bbcd98bd16daad20904"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2c1143564c71e7497b42d8360a8379ccbb011d3c"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/3485c7236c59c8c34a41af1c4b52982437554e79"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/daf23014e5d975e72ea9c02b5160d3fcf070ea47"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f743eab6486965f276c7e3f1700895f014fdc6db"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}


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