{"affected":[{"defaultStatus":"unaffected","ecosystem":"https://github.com/zephyrproject-rtos/zephyr","packageName":"zephyr","product":"zephyr","source":"CNA: zephyr","vendor":"zephyrproject","versions":[{"lessThan":"4.3.2","status":"affected","version":"4.3.0","versionType":"semver"},{"lessThan":"4.5.0","status":"affected","version":"4.4.0","versionType":"semver"}]}],"cveId":"CVE-2026-85036","cwes":["CWE-666"],"description":"The Bluetooth Classic AVDTP layer defers releasing a session's stream endpoints: bt_avdtp_l2cap_disconnected() in subsys/bluetooth/host/classic/avdtp.c ends with k_work_submit(&session->_release_work), placing the embedded struct k_work on the system work queue's pending list. When the same struct bt_avdtp object is immediately reused for a new signalling connection, the session memory is re-initialized — a2dp_get_connection() in subsys/bluetooth/host/classic/a2dp.c memset()s the whole struct bt_a2dp, and bt_avdtp_l2cap_accept() / bt_avdtp_connect() call k_work_init() on session->_release_work — while that work item is still linked into k_sys_work_q.pending. Zeroing a linked sys_snode_t truncates the list while its tail pointer keeps pointing past the truncation.\n\nThe reuse window is deterministic rather than a race. All host RX processing runs on the Bluetooth RX work queue at a cooperative priority (CONFIG_BT_RX_PRIO), while _release_work is submitted to the lower-priority system work queue, so the release handler cannot run until the RX thread blocks. Because l2cap_br_recv() processes every signalling command contained in a single L2CAP signalling PDU back-to-back, a peer can send one PDU holding an L2CAP Disconnection Request for the AVDTP signalling channel followed by a Connection Request for PSM 0x0019; the second command reaches the session-reuse path with the release work provably still queued. The peer must already hold an encrypted AVDTP signalling channel, i.e. be a paired/bonded BR/EDR device.\n\nThe result is corruption of the global system work queue's pending list: either the queue silently stops executing any work at all (subsequent submissions are appended to a chain the head can no longer reach, and the orphaned items keep their K_WORK_QUEUED flag forever) or, in the tail variant, the list acquires a self-referencing node that the queue thread spins on. The written values are pointers to other struct k_work objects and are not attacker-controlled, so the impact is a device-wide, reboot-required denial of service rather than a controllable write primitive. Only builds with CONFIG_BT_CLASSIC and CONFIG_BT_A2DP are affected.\n\nThe fix is a two-commit unit, and neither commit closes the path on its own. ec822ceed83b adds a pending-release check to bt_avdtp_connect() and bt_avdtp_l2cap_accept(), but the A2DP upper layer's a2dp_get_connection() memset()s the session — including the queued work item's list node and flags — before those checks run, so k_work_busy_get() would observe an already-cleared state. 2bd5ea88c69b closes that by making a2dp_get_connection() itself skip the reuse and return NULL while the release work is still pending, which both callers already handle by rejecting the connection attempt. Apply both commits together; either one alone leaves the device vulnerable.","epss":null,"exploits":[],"kev":null,"metrics":[{"score":5.7,"severity":"medium","source":"CNA: zephyr","vector":"CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","version":"3.1"}],"modifiedAt":1793772541385,"publishedAt":1793772541385,"references":[{"source":"CNA: zephyr","tags":["patch"],"url":"https://github.com/zephyrproject-rtos/zephyr/commit/ec822ceed83b5008d4a28700fdacf2ff80020963"},{"source":"CNA: zephyr","tags":["patch"],"url":"https://github.com/zephyrproject-rtos/zephyr/commit/2bd5ea88c69bdd94fc5a9e6757b29e1de9903ef5"},{"source":"CNA: zephyr","tags":[],"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-ffxg-752w-mv9x"}],"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/ec822ceed83b5008d4a28700fdacf2ff80020963"},{"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/2bd5ea88c69bdd94fc5a9e6757b29e1de9903ef5"}],"revision":"0523f8f2914c36f15c4556d361cc25fcf9d14aaea2d27ceaf9007ac37225e123","sources":[{"modifiedAt":1793772541385,"name":"CNA: zephyr","retrievedAt":1793776162390,"url":"https://www.cve.org/CVERecord?id=CVE-2026-85036"}],"ssvc":null,"status":"published","title":"Bluetooth Classic AVDTP session reuse re-initializes a queued work item, corrupting the system work queue","updatedAt":1793776162390}