{"id":"CVE-2026-85033","title":"Bluetooth Classic AVRCP Target: missing TX cleanup on disconnect permanently stalls vendor-dependent responses and leaks them to the next peer","summary":"The AVRCP Target role in subsys/bluetooth/host/classic/avrcp.c keeps its vendor-dependent response transmit state in a per-connection object selected by connection index (get_avrcp_tg()), with the per-transfer context (tid, sent_len, and…","severity":"medium","cvss":4.6,"cvssVector":"CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:L","cvssSource":"cna","cwe":["CWE-459"],"vendor":"zephyrproject","product":"zephyr","affected":["zephyr >= 4.4.0 < 4.5.0"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-11-03T18:15:37.681298Z"},"published":"2026-11-03","updated":"2026-11-03","sourceUpdated":"2026-11-03T18:15:47.700Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-85033","references":[{"url":"https://github.com/zephyrproject-rtos/zephyr/commit/47728746bb52863607f06072c13a0a524ad6b654","label":"Fix commit"},{"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-2fqc-xhj4-qvp7","label":"GHSA-2fqc-xhj4-qvp7"}],"tags":["cve.org"],"epss":0.00215,"epssPercentile":0.1193,"ingestedAt":"2026-11-05T20:33:06.342Z","slug":"CVE-2026-85033","body":"## Overview\n\nThe AVRCP Target role in subsys/bluetooth/host/classic/avrcp.c keeps its vendor-dependent response transmit state in a per-connection object selected by connection index (get_avrcp_tg()), with the per-transfer context (tid, sent_len, and the BT_AVRCP_TG_FLAG_TX_ONGOING flag) stored in the user_data of the queued response net_buf. The AVCTP teardown handler avrcp_disconnected() did not cancel tg->vd_rsp_tx_work and did not release the buffers still queued on tg->vd_rsp_tx_pending, so a link drop in the middle of a fragmented response left the buffer on the list with TX_ONGOING still set.\n\nA remote AVRCP Controller can trigger this deterministically: it issues a vendor-dependent command whose response exceeds one AVRCP fragment (for example GetElementAttributes or GetCapabilities), lets bt_avrcp_tg_vendor_tx_work() emit the START fragment, and then drops the ACL link instead of sending REQUEST_CONTINUING_RESPONSE. The AVCTP control channel requires an encrypted BR/EDR link (BT_SECURITY_L2), so the attacker must be a paired peer within radio range; no user interaction is needed.\n\nBecause the Target objects are static and reused, the next connection landing on the same connection index finds the stale buffer at the head of vd_rsp_tx_pending. Every run of the TX work sees TX_ONGOING and returns immediately, so all further vendor-dependent responses queue behind the stale head and are never sent — a persistent loss of AVRCP Target function that no timeout clears and only a reboot recovers. Each cycle also leaks one response buffer from a shallow application pool, and a new peer that sends REQUEST_CONTINUING_RESPONSE clears the stale TX_ONGOING via bt_avrcp_tg_process_continuing_cmd(), causing the un-sent remainder of the previous peer's response to be transmitted to it.\n\nThe fix cancels tg->vd_rsp_tx_work and unrefs every buffer on tg->vd_rsp_tx_pending in avrcp_disconnected(); since the TX context lives in the buffer user_data, releasing the buffers also resets the TX state machine. There is no memory corruption: the pre-fix buffer is leaked with a live reference, so no use-after-free arises.\n\n## Affected\n\n- `zephyr >= 4.4.0 < 4.5.0`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":25,"depthScoreParts":{"impact":25.3,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}