GHSA-F6GP-JXPH-7WJ2
Vulnerability from github – Published: 2026-07-25 12:31 – Updated: 2026-09-04 15:35In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: ISO: avoid NULL deref of conn in iso_conn_big_sync()
iso_conn_big_sync() drops the socket lock to call hci_get_route() and then re-acquires it, but dereferences iso_pi(sk)->conn->hcon afterwards without re-checking that conn is still valid.
While the lock is dropped, the connection can be torn down under the same socket lock: iso_disconn_cfm() -> iso_conn_del() -> iso_chan_del() sets iso_pi(sk)->conn to NULL (and the broadcast teardown path can also clear conn->hcon on its own). When iso_conn_big_sync() re-acquires the lock and reads conn->hcon, conn may be NULL, causing a NULL pointer dereference (hcon is the first member of struct iso_conn).
This path is reached from iso_sock_recvmsg() for a PA-sync broadcast sink socket (BT_SK_DEFER_SETUP | BT_SK_PA_SYNC), so the dropped-lock window can race with connection teardown driven by controller events.
Re-validate iso_pi(sk)->conn and its hcon after re-acquiring the socket lock and bail out if the connection went away, as already done in the sibling iso_sock_rebind_bc().
{
"affected": [],
"aliases": [
"CVE-2026-64404"
],
"database_specific": {
"cwe_ids": [
"CWE-476"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-07-25T10:17:24Z",
"severity": "MODERATE"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: ISO: avoid NULL deref of conn in iso_conn_big_sync()\n\niso_conn_big_sync() drops the socket lock to call hci_get_route() and\nthen re-acquires it, but dereferences iso_pi(sk)-\u003econn-\u003ehcon afterwards\nwithout re-checking that conn is still valid.\n\nWhile the lock is dropped, the connection can be torn down under the\nsame socket lock: iso_disconn_cfm() -\u003e iso_conn_del() -\u003e iso_chan_del()\nsets iso_pi(sk)-\u003econn to NULL (and the broadcast teardown path can also\nclear conn-\u003ehcon on its own). When iso_conn_big_sync() re-acquires the\nlock and reads conn-\u003ehcon, conn may be NULL, causing a NULL pointer\ndereference (hcon is the first member of struct iso_conn).\n\nThis path is reached from iso_sock_recvmsg() for a PA-sync broadcast\nsink socket (BT_SK_DEFER_SETUP | BT_SK_PA_SYNC), so the dropped-lock\nwindow can race with connection teardown driven by controller events.\n\nRe-validate iso_pi(sk)-\u003econn and its hcon after re-acquiring the socket\nlock and bail out if the connection went away, as already done in the\nsibling iso_sock_rebind_bc().",
"id": "GHSA-f6gp-jxph-7wj2",
"modified": "2026-09-04T15:35:53Z",
"published": "2026-07-25T12:31:34Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64404"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/01afd198c2c286cd3b81f44d4e33a2e638711550"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b3e647a4aa4d2d054f86a783f5c426035e1dc237"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/b84eeb7636d6962dd882d5e0b31475e4f404313c"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d5541eb148da72d5e0a1bca8ecd171f9fc8b366f"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
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