GHSA-P6R7-4GCJ-HHQQ
Vulnerability from github – Published: 2026-09-04 18:31 – Updated: 2026-09-04 18:31In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: MGMT: reject HCI_CMD_SYNC params_len above 255
mgmt_hci_cmd_sync() checks that the message length agrees with params_len but puts no upper bound on it. params_len is __le16 while the parameter length in the HCI command header is a u8:
struct hci_command_hdr {
__le16 opcode;
__u8 plen;
} __packed;
hci_cmd_sync_alloc() assigns one to the other:
hdr->plen = plen;
if (plen)
skb_put_data(skb, param, plen);
so a params_len of 256 leaves plen at 0 while all 256 bytes are still appended. The frame handed to the driver then declares no parameters and carries 256 of them. On a length framed transport such as H:4 the controller takes the trailing bytes as the start of the next packet.
The mgmt socket MTU is HCI_MAX_FRAME_SIZE, so params_len can reach about 1KB this way. Commit 03f1700b9b4d ("Bluetooth: MGMT: reject malformed HCI_CMD_SYNC commands") only made params_len agree with the message length, a value that fits the message but not the header field is still accepted.
Reject params_len that does not fit the header field.
{
"affected": [],
"aliases": [
"CVE-2026-80760"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-04T16:18:01Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: MGMT: reject HCI_CMD_SYNC params_len above 255\n\nmgmt_hci_cmd_sync() checks that the message length agrees with params_len\nbut puts no upper bound on it. params_len is __le16 while the parameter\nlength in the HCI command header is a u8:\n\n\tstruct hci_command_hdr {\n\t\t__le16\topcode;\n\t\t__u8\tplen;\n\t} __packed;\n\nhci_cmd_sync_alloc() assigns one to the other:\n\n\thdr-\u003eplen = plen;\n\n\tif (plen)\n\t\tskb_put_data(skb, param, plen);\n\nso a params_len of 256 leaves plen at 0 while all 256 bytes are still\nappended. The frame handed to the driver then declares no parameters and\ncarries 256 of them. On a length framed transport such as H:4 the\ncontroller takes the trailing bytes as the start of the next packet.\n\nThe mgmt socket MTU is HCI_MAX_FRAME_SIZE, so params_len can reach about\n1KB this way. Commit 03f1700b9b4d (\"Bluetooth: MGMT: reject malformed\nHCI_CMD_SYNC commands\") only made params_len agree with the message\nlength, a value that fits the message but not the header field is still\naccepted.\n\nReject params_len that does not fit the header field.",
"id": "GHSA-p6r7-4gcj-hhqq",
"modified": "2026-09-04T18:31:24Z",
"published": "2026-09-04T18:31:24Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80760"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0bd0195ce25737cbdd0eabc54319ee0ddf3a0ad2"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/5d95286b6d6e8f1d304da7522bfa6860fc017e48"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6e1c44878aa3ee7336efeaf01414b030b0a5c273"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b7d9edcf9fe6e9ec3a2e80ef9e8d44ef9b4f2894"
}
],
"schema_version": "1.4.0",
"severity": []
}
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