GHSA-G55X-63CP-X552
Vulnerability from github – Published: 2026-10-23 15:31 – Updated: 2026-10-24 15:32In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: ISO: Serialize concurrent connect calls
iso_sock_connect() checks the socket state before taking the socket lock and drops the lock again before setting up a connection. Two callers can both pass the admission check while the socket is open or bound.
Caller A can copy its destination for route selection, then caller B can replace the socket destination before A binds or connects the CIS. A then uses B's destination with the route selected for its own request. B can also proceed after A attaches a connection and sets BT_CONNECT. For deferred BIS setup, B can bind a second BIS and overwrite iso_pi(sk)->conn, leaving the first connection's reference and conn->sk back-pointer stranded. Concurrent CIS connects can likewise replace the socket's connection. Later teardown only detaches the current connection, so a callback on the old connection can race with socket release and access a freed socket.
KASAN reported:
BUG: KASAN: slab-use-after-free in iso_sock_hold+0xf7/0x1b0 Call Trace: iso_sock_hold+0xf7/0x1b0 iso_conn_del+0x7b/0x1d0 iso_connect_cfm+0x186/0x16a0 hci_conn_failed+0x154/0x280 hci_abort_conn_sync+0x3dc/0x7d0 hci_cmd_sync_work+0x173/0x300
Allocated by task 121: sk_alloc+0x2b/0x6d0 bt_sock_alloc+0x29/0x370 iso_sock_alloc.constprop.0+0x19/0x300 iso_sock_create+0x94/0x100
Freed by task 121: kfree+0x121/0x3c0 __sk_destruct+0x42b/0x540 iso_sock_release+0x29d/0x340 __sock_release+0xa1/0x260
Check admission under the socket lock and mark the connect operation in progress before publishing its destination. Keep that flag set across route lookup and connection setup, rejecting another connect with -EBADFD before it can change the destination or attach a connection. Clear the flag after either helper returns, including on failure, so a failed setup can be retried.
A separate flag is needed because the socket lock must be released before acquiring the HCI device lock, while BT_CONNECT requires an attached connection. Keep the existing state transitions and the deferred CIS completion through iso_sock_recvmsg().
Reject an existing socket attachment in __iso_chan_add() before taking a new reference or publishing either pointer, so every caller preserves the connection association. Keep the same-socket, same-connection success case for deferred CIS setup. Reject an attached socket before BIS setup so a reusable BIS is not claimed before the attachment is rejected.
In CIS setup, reject a different HCI connection before iso_conn_add() and drop the per-attempt HCI hold directly. An unowned iso_conn may still carry another reference after detachment, so its destruction cannot be relied on to release that hold.
iso_listen_bis() creates a fresh PA HCI/ISO pair under the device lock, so the temporary iso_conn_put() frees the ISO candidate and drops its HCI hold on rejection. iso_conn_ready() uses a freshly allocated, unpublished child with no connection, making the socket-side rejection unreachable.
{
"affected": [],
"aliases": [
"CVE-2026-99012"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-10-23T13:17:23Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: ISO: Serialize concurrent connect calls\n\niso_sock_connect() checks the socket state before taking the socket lock\nand drops the lock again before setting up a connection. Two callers can\nboth pass the admission check while the socket is open or bound.\n\nCaller A can copy its destination for route selection, then caller B can\nreplace the socket destination before A binds or connects the CIS. A\nthen uses B\u0027s destination with the route selected for its own request.\nB can also proceed after A attaches a connection and sets BT_CONNECT.\nFor deferred BIS setup, B can bind a second BIS and overwrite\niso_pi(sk)-\u003econn, leaving the first connection\u0027s reference and conn-\u003esk\nback-pointer stranded. Concurrent CIS connects can likewise replace the\nsocket\u0027s connection. Later teardown only detaches the current connection,\nso a callback on the old connection can race with socket release and\naccess a freed socket.\n\nKASAN reported:\n\n BUG: KASAN: slab-use-after-free in iso_sock_hold+0xf7/0x1b0\n Call Trace:\n iso_sock_hold+0xf7/0x1b0\n iso_conn_del+0x7b/0x1d0\n iso_connect_cfm+0x186/0x16a0\n hci_conn_failed+0x154/0x280\n hci_abort_conn_sync+0x3dc/0x7d0\n hci_cmd_sync_work+0x173/0x300\n\n Allocated by task 121:\n sk_alloc+0x2b/0x6d0\n bt_sock_alloc+0x29/0x370\n iso_sock_alloc.constprop.0+0x19/0x300\n iso_sock_create+0x94/0x100\n\n Freed by task 121:\n kfree+0x121/0x3c0\n __sk_destruct+0x42b/0x540\n iso_sock_release+0x29d/0x340\n __sock_release+0xa1/0x260\n\nCheck admission under the socket lock and mark the connect operation in\nprogress before publishing its destination. Keep that flag set across\nroute lookup and connection setup, rejecting another connect with\n-EBADFD before it can change the destination or attach a connection.\nClear the flag after either helper returns, including on failure, so a\nfailed setup can be retried.\n\nA separate flag is needed because the socket lock must be released before\nacquiring the HCI device lock, while BT_CONNECT requires an attached\nconnection. Keep the existing state transitions and the deferred CIS\ncompletion through iso_sock_recvmsg().\n\nReject an existing socket attachment in __iso_chan_add() before taking\na new reference or publishing either pointer, so every caller preserves\nthe connection association. Keep the same-socket, same-connection success\ncase for deferred CIS setup. Reject an attached socket before BIS setup\nso a reusable BIS is not claimed before the attachment is rejected.\n\nIn CIS setup, reject a different HCI connection before iso_conn_add()\nand drop the per-attempt HCI hold directly. An unowned iso_conn may still\ncarry another reference after detachment, so its destruction cannot be\nrelied on to release that hold.\n\niso_listen_bis() creates a fresh PA HCI/ISO pair under the device lock,\nso the temporary iso_conn_put() frees the ISO candidate and drops its\nHCI hold on rejection. iso_conn_ready() uses a freshly allocated,\nunpublished child with no connection, making the socket-side rejection\nunreachable.",
"id": "GHSA-g55x-63cp-x552",
"modified": "2026-10-24T15:32:49Z",
"published": "2026-10-23T15:31:34Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-99012"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/1adcfe232c0f58890c2538211a841100ad0512bd"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/3728f6b0d5990c0d500e929ba10baf93bee24f5e"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9b6ed57eb8c892ee7566b8c1bd06fdd0053b53de"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c6489a3a0ac8c07f64cb5b44f005bc518f1048ac"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/e32d80293a0e1a160d5e5101daa8c82148c07510"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Vulnerability timeline
Sightings and recorded dates, grouped by day · UTC
Loading timeline…
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.