{"id":"CVE-2026-85033","aliases":[],"cve":{"records":[{"id":"CVE-2026-85033","source":"zephyr","state":"PUBLISHED","reasons":[],"replacements":[],"disputed":false,"unsupportedWhenAssigned":false,"reserved":"2026-09-02T20:23:14.098Z","published":"2026-11-03T13:36:06.746Z","modified":"2026-11-03T18:15:47.700Z"}],"publishers":[{"name":"zephyr","role":"CNA","organizationId":"e2e69745-5e70-4e92-8431-deb5529a81ad","modified":"2026-11-03T13:36:06.746Z"},{"name":"CISA-ADP","role":"ADP","organizationId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","modified":"2026-11-03T18:15:47.700Z"}],"references":[{"url":"https://github.com/zephyrproject-rtos/zephyr/commit/47728746bb52863607f06072c13a0a524ad6b654","tags":["patch"],"source":"zephyr"},{"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-2fqc-xhj4-qvp7","tags":[],"source":"zephyr"}],"weaknesses":[{"id":"CWE-459","description":"dos","source":"zephyr"}],"applicability":[],"prioritization":[{"source":"CISA-ADP","type":"SSVC","role":"CISA Coordinator","timestamp":"2026-11-03T18:15:37.681298Z","decisions":[{"name":"Exploitation","value":"none"},{"name":"Automatable","value":"no"},{"name":"Technical Impact","value":"partial"}]}]},"title":"Bluetooth Classic AVRCP Target: missing TX cleanup on disconnect permanently stalls vendor-dependent responses and leaks them to the next peer","titleSource":"zephyr","descriptionSource":"zephyr","description":"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 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.","score":4.6,"severity":"medium","published":"2026-11-03T13:36:06.746Z","modified":"2026-11-03T18:15:47.700Z","withdrawn":false,"knownExploited":false,"affected":[],"products":[{"vendor":"zephyrproject","name":"zephyr","platforms":[],"versions":[{"version":"4.4.0","status":"affected","lessThan":"4.5.0","versionType":"semver"}],"defaultStatus":"unaffected","cpes":[],"source":"zephyr","url":"https://www.cve.org/CVERecord?id=CVE-2026-85033"}],"remediation":[],"references":["https://github.com/zephyrproject-rtos/zephyr/commit/47728746bb52863607f06072c13a0a524ad6b654","https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-2fqc-xhj4-qvp7"],"sources":[{"name":"CVE","id":"CVE-2026-85033","modified":"2026-11-03T18:15:47.700Z","url":"https://www.cve.org/CVERecord?id=CVE-2026-85033"}],"assessments":[{"source":"zephyr","vector":"CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:L","score":4.6}],"sourceAffected":[],"observedAt":"2026-11-03T18:20:54.755Z","kev":{"status":"not-listed","checkedAt":"2026-11-14T23:50:31.991Z"},"coverage":[{"source":"NVD","status":"no-result","checkedAt":"2026-11-03T13:45:35.724Z","attemptedAt":"2026-11-03T13:45:35.724Z"},{"source":"GHSA","status":"no-result","checkedAt":"2026-11-03T13:45:35.723Z","attemptedAt":"2026-11-03T13:45:35.723Z"},{"source":"EUVD","status":"no-result","checkedAt":"2026-11-03T13:45:36.007Z","attemptedAt":"2026-11-03T13:45:36.007Z"},{"source":"EPSS","status":"no-result","checkedAt":"2026-11-03T13:45:35.549Z","attemptedAt":"2026-11-03T13:45:35.549Z"}],"evidence":[],"aiSummary":{"text":"Zephyr 4.4.0 is affected by a vulnerability where a paired peer can trigger a persistent loss of AVRCP Target function by dropping the ACL link during a fragmented response. The next connection may also receive leaked response buffers. A reboot is required to recover.","model":"@cf/meta/llama-3.3-70b-instruct-fp8-fast","generatedAt":"2026-11-03T13:41:03.773Z","sources":[{"name":"CVE","url":"https://www.cve.org/CVERecord?id=CVE-2026-85033"}]}}