{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-90093", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.786Z", "datePublished": "2026-09-17T16:06:06.843Z", "dateUpdated": "2026-10-21T12:49:48.027Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-21T12:49:48.027Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: L2CAP: access chan->conn safely in get/setsockopt\n\nSince commit b66774b48dd9 (\"Bluetooth: L2CAP: Fix UAF in channel timeout by holding conn ref\")\nl2cap_chan::conn has held reference and remains non-NULL also after the\ncorresponding hci_conn is deleted. In this state accessing various\nfields eg. hci_conn::hdev is invalid, which leads to KASAN crash in\nl2cap_sock_setsockopt() access of conn->hcon->hdev.\n\nCheck l2cap_chan::conn.hcon corresponds to an alive hci_conn before\ntrying to use it in l2cap_sock.c. Hold l2cap_chan_lock() in\ngetsockopt/setsockopt to ensure it stays alive, and to avoid data races\nin l2cap_chan fields." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The UAF is reached from __sys_setsockopt/__sys_getsockopt_iter into l2cap_sock_setsockopt()/l2cap_sock_getsockopt(), which dereference chan->conn->hcon->hdev after the HCI device is already gone; the trigger is the local BT_FLUSHABLE/BT_SECURITY/BT_PHY sockopt, not a received L2CAP or HCI PDU. Syzbot frees that hdev via vhci_release()->hci_unregister_dev(), which an in-range peer cannot invoke.\nAC:L - After b66774b48dd9, l2cap_chan_del() sets FLAG_DEL but leaves chan->conn non-NULL, so a later setsockopt(SOL_BLUETOOTH, BT_FLUSHABLE, BT_FLUSHABLE_OFF) deterministically hits lmp_no_flush_capable(conn->hcon->hdev) on the deleted hci_conn. The attacker opens the L2CAP socket, tears down the controller (close of /dev/vhci), then issues the sockopt; no un-controllable race or rare config is required.\nPR:L - l2cap_sock_create() requires capable(CAP_NET_RAW) only for SOCK_RAW; SOCK_SEQPACKET/STREAM/DGRAM L2CAP sockets used here have no capability gate, and vhci_open() likewise has no capable() check. An unprivileged init_net user who can open /dev/vhci (or an equivalent HCI node) can create the socket, unregister the controller, and call setsockopt without real root.\nUI:N - The attacker owns both the AF_BLUETOOTH/BTPROTO_L2CAP fd and the teardown fd: they connect, close /dev/vhci so hci_conn_hash_flush()->l2cap_conn_del() runs, then call setsockopt on their still-open socket. No other user must pair, mount, or click anything.\nS:U - l2cap_sock_setsockopt() is using a dangling hci_dev through l2cap_conn->hcon after hci_release_dev(); the resulting slab UAF stays inside the host kernel Bluetooth stack and does not cross a VM, IOMMU, or sandbox authority.\nC:H - KASAN reports a use-after-free/OOB read in l2cap_sock_setsockopt() of conn->hcon->hdev (lmp_no_flush_capable() reads hdev->features[0][6]; getsockopt BT_SECURITY/BT_PHY and L2CAP_CONNINFO also read hcon fields). The freed hci_dev slab was reused as skbuff_small_head, so spraying that object yields a kernel-memory read primitive through the dangling hdev pointer.\nI:H - The same dangling conn->hcon remains usable from setsockopt after FLAG_DEL: BT_SECURITY on an ATT socket calls smp_conn_security(conn->hcon) which touches hcon->hdev flags and hcon->pending_sec_level, and BT_PHY calls hci_conn_set_phy() on that hcon. A sprayed hci_dev in place of the freed object supplies function pointers (send/reset/workqueues) for write and control-flow hijack.\nA:H - Syzbot crashed in l2cap_sock_setsockopt+0x22c3 (net/bluetooth/l2cap_sock.c:1003) with both KASAN slab-out-of-bounds and use-after-free reads of the released hci_dev after vhci_release()->hci_release_dev(). Any such UAF dereference oopses or panics the kernel and can be repeated by open/connect/close/setsockopt." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/bluetooth/l2cap_sock.c" ], "versions": [ { "version": "91047a4396a8b1857a6f712a90cf33ec0012b189", "lessThan": "19e154d794eb4d33d99ca4a087b1cea9d5e65786", "status": "affected", "versionType": "git" }, { "version": "0b0e2bf39cf99e458d991b9df253727e036a7d7d", "lessThan": "3af72bf8f73c519ee562e6963d5ff8e678924f93", "status": "affected", "versionType": "git" }, { "version": "d3b739db5dc6f688a60d56da872fabaf65246032", "lessThan": "8460dc49c9756a1e9288218060b4d41e1b704905", "status": "affected", "versionType": "git" }, { "version": "b66774b48dd98f07254951f74ea6f513efe7ff8b", "lessThan": "f49321c85785178214fd67f2e9b4b73d6363783b", "status": "affected", "versionType": "git" }, { "version": "b66774b48dd98f07254951f74ea6f513efe7ff8b", "lessThan": "ca2c4c26498643f421d35ffe258fafbd3ed461c3", "status": "affected", "versionType": "git" }, { "version": "8f90405a4a6f1f1880dc07996b47bf57c712bd8a", "status": "affected", "versionType": "git" }, { "version": "32d783cafb46ff3ca58e6f9fd62c9c5f35eaf26b", "status": "affected", "versionType": "git" }, { "version": "8922c7940bae9ce4b1736dddb6362370793835c2", "status": "affected", "versionType": "git" }, { "version": "50c38d9f42a529691e4e67ea9cedf4f0bfc8d277", "status": "affected", "versionType": "git" }, { "version": "6.6.145", "lessThan": "6.6.160", "status": "affected", "versionType": "semver" }, { "version": "6.12.97", "lessThan": "6.12.114", "status": "affected", "versionType": "semver" }, { "version": "6.18.39", "lessThan": "6.18.57", "status": "affected", "versionType": "semver" }, { "version": "5.10.265", "lessThan": "5.11", "status": "affected", "versionType": "semver" }, { "version": "5.15.216", "lessThan": "5.16", "status": "affected", "versionType": "semver" }, { "version": "6.1.183", "lessThan": "6.2", "status": "affected", "versionType": "semver" }, { "version": "7.1.4", "lessThan": "7.2", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/bluetooth/l2cap_sock.c" ], "versions": [ { "version": "7.2", "status": "affected" }, { "version": "0", "lessThan": "7.2", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.160", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.114", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.57", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.6", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6.145", "versionEndExcluding": "6.6.160" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12.97", "versionEndExcluding": "6.12.114" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.18.39", "versionEndExcluding": "6.18.57" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.2", "versionEndExcluding": "7.2.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.2", "versionEndExcluding": "7.3" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10.265" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15.216" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1.183" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.1.4" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/19e154d794eb4d33d99ca4a087b1cea9d5e65786" }, { "url": "https://git.kernel.org/stable/c/3af72bf8f73c519ee562e6963d5ff8e678924f93" }, { "url": "https://git.kernel.org/stable/c/8460dc49c9756a1e9288218060b4d41e1b704905" }, { "url": "https://git.kernel.org/stable/c/f49321c85785178214fd67f2e9b4b73d6363783b" }, { "url": "https://git.kernel.org/stable/c/ca2c4c26498643f421d35ffe258fafbd3ed461c3" } ], "title": "Bluetooth: L2CAP: access chan->conn safely in get/setsockopt", "x_generator": { "engine": "bippy-1.2.0" } } } }