{"affected":[{"defaultStatus":"unaffected","ecosystem":"https://github.com/zephyrproject-rtos/zephyr","packageName":"zephyr","product":"zephyr","source":"CNA: zephyr","vendor":"zephyrproject","versions":[{"lessThanOrEqual":"4.4.2","status":"affected","version":"3.3.0","versionType":"semver"}]}],"cveId":"CVE-2026-79982","cwes":["CWE-787"],"description":"The Bluetooth HCI USB transport class of the new USB device stack, subsys/usb/device_next/class/bt_hci.c, copies every controller-to-host HCI packet into a USB transfer buffer before enqueuing it on an endpoint. bt_hci_tx_sync_in() allocated that buffer from bt_hci_ep_pool, a fixed pool whose slots are only USBD_MAX_BULK_MPS bytes (64 on full-speed-only builds), and then performed net_buf_add_mem(buf, bt_buf->data, bt_buf->len) with no length check. HCI event and ACL buffers are sized by CONFIG_BT_BUF_EVT_RX_SIZE and CONFIG_BT_BUF_ACL_RX_SIZE and can be far larger, so the copy runs past the end of the 64-byte slot into the adjacent slots and into whatever follows the statically allocated pool.\n\nThe device runs the local Bluetooth controller in raw HCI mode (CONFIG_BT_HCI_RAW), so the oversized packets originate over the air. With the HCI buffer sizes recommended for full-featured controllers, an unauthenticated attacker within Bluetooth range can supply the overflowing bytes: a connected peer that negotiates Data Length Extension can send ACL fragments up to CONFIG_BT_CTLR_DATA_LENGTH_MAX bytes, and an attacker that merely broadcasts extended advertising data reaches the same path through LE Extended Advertising Report events, which the controller fragments only to CONFIG_BT_BUF_EVT_RX_SIZE. In the stock configuration the overflow is already reached without any radio traffic: the mandatory Read Supported Commands command-complete event is 70 bytes and overruns the 64-byte slot by six bytes on every host initialization.\n\nBecause net_buf_add_mem() validates tailroom only through an assertion unless CONFIG_NET_BUF_HARDENING is enabled, builds with CONFIG_ASSERT=n — the usual production setting — silently corrupt memory adjacent to the USB buffer pool with attacker-chosen contents, which on a target without memory protection between subsystems can lead to arbitrary code execution. Builds with assertions enabled fail the assertion instead and panic, giving a remotely triggerable denial of service. The fix introduces a separate bt_hci_tx_pool sized to MAX(BT_BUF_ACL_RX_SIZE, BT_BUF_EVT_RX_SIZE) for the controller-to-host direction while leaving the host-to-device pool at the endpoint packet size, which is already bounds-checked during reassembly.","epss":{"date":"2026-11-02","percentile":0.1377,"score":0.00229},"exploits":[],"kev":null,"metrics":[{"score":8.8,"severity":"high","source":"CNA: zephyr","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"},{"score":8.8,"severity":"high","source":"NVD: vulnerabilities@zephyrproject.org","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","version":"3.1"}],"modifiedAt":1793636264307,"publishedAt":1792785379432,"references":[{"source":"CNA: zephyr","tags":["patch"],"url":"https://github.com/zephyrproject-rtos/zephyr/commit/0419defd2391652edc27689d206fcd9c48439d4a"},{"source":"CNA: zephyr","tags":[],"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-w5px-w97v-c3hj"},{"source":"vulnerabilities@zephyrproject.org","tags":[],"url":"https://github.com/zephyrproject-rtos/zephyr/commit/0419defd2391652edc27689d206fcd9c48439d4a"},{"source":"vulnerabilities@zephyrproject.org","tags":[],"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-w5px-w97v-c3hj"}],"remediation":[{"kind":"fix","source":"CNA: zephyr","text":"The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.","url":"https://github.com/zephyrproject-rtos/zephyr/commit/0419defd2391652edc27689d206fcd9c48439d4a"}],"revision":"ec2645db8153f678ad061dcaf1055e53f92d9b0dedb1763c94fc13e7124b25b0","sources":[{"modifiedAt":1793634989127,"name":"CNA: zephyr","retrievedAt":1793639372357,"url":"https://www.cve.org/CVERecord?id=CVE-2026-79982"},{"modifiedAt":1793636264307,"name":"NVD","retrievedAt":1793643436227,"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-79982"},{"modifiedAt":null,"name":"FIRST EPSS","retrievedAt":1793635806261,"url":"https://api.first.org/data/v1/epss?cve=CVE-2026-79982"}],"ssvc":{"assessedAt":1793634921632,"automatable":"no","exploitation":"none","source":"ADP: CISA-ADP","technicalImpact":"total"},"status":"published","title":"Out-of-bounds write in the USB Bluetooth HCI transport class when a controller-to-host HCI packet exceeds the bulk endpoint maximum packet size","updatedAt":1793643436227}