{"api_version":"1","generated_at":"2026-11-04T09:47:58+00:00","cve":"CVE-2026-85036","urls":{"html":"https://cve.report/CVE-2026-85036","api":"https://cve.report/api/cve/CVE-2026-85036.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-85036","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-85036"},"summary":{"title":"Bluetooth Classic AVDTP session reuse re-initializes a queued work item, corrupting the system work queue","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.","state":"PUBLISHED","assigner":"zephyr","published_at":"2026-11-04 06:17:06","updated_at":"2026-11-04 06:17:06"},"problem_types":["CWE-666","CWE-666 memory-safety"],"metrics":[{"version":"3.1","source":"vulnerabilities@zephyrproject.org","type":"Secondary","score":"5.7","severity":"MEDIUM","vector":"CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","baseScore":5.7,"baseSeverity":"MEDIUM","attackVector":"ADJACENT_NETWORK","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"CVSS","score":"5.7","severity":"MEDIUM","vector":"CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","data":{"baseScore":5.7,"baseSeverity":"MEDIUM","vectorString":"CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","version":"3.1"}}],"references":[{"url":"https://github.com/zephyrproject-rtos/zephyr/commit/ec822ceed83b5008d4a28700fdacf2ff80020963","name":"https://github.com/zephyrproject-rtos/zephyr/commit/ec822ceed83b5008d4a28700fdacf2ff80020963","refsource":"vulnerabilities@zephyrproject.org","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-ffxg-752w-mv9x","name":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-ffxg-752w-mv9x","refsource":"vulnerabilities@zephyrproject.org","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/zephyrproject-rtos/zephyr/commit/2bd5ea88c69bdd94fc5a9e6757b29e1de9903ef5","name":"https://github.com/zephyrproject-rtos/zephyr/commit/2bd5ea88c69bdd94fc5a9e6757b29e1de9903ef5","refsource":"vulnerabilities@zephyrproject.org","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-85036","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-85036","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"zephyrproject","product":"zephyr","version":"affected 4.3.0 4.3.2 semver","platforms":[]},{"source":"CNA","vendor":"zephyrproject","product":"zephyr","version":"affected 4.4.0 4.5.0 semver","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"collectionURL":"https://github.com/zephyrproject-rtos/zephyr","defaultStatus":"unaffected","packageName":"zephyr","product":"zephyr","programFiles":["subsys/bluetooth/host/classic/a2dp.c","subsys/bluetooth/host/classic/avdtp.c"],"programRoutines":[{"name":"a2dp_get_connection"},{"name":"bt_avdtp_connect"},{"name":"bt_avdtp_l2cap_accept"},{"name":"bt_avdtp_l2cap_disconnected"}],"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"}]}],"descriptions":[{"lang":"en","value":"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."}],"metrics":[{"cvssV3_1":{"baseScore":5.7,"baseSeverity":"MEDIUM","vectorString":"CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"format":"CVSS"}],"problemTypes":[{"descriptions":[{"cweId":"CWE-666","description":"memory-safety","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-11-04T06:09:01.385Z","orgId":"e2e69745-5e70-4e92-8431-deb5529a81ad","shortName":"zephyr"},"references":[{"name":"Fix commit ec822ceed83b","tags":["patch"],"url":"https://github.com/zephyrproject-rtos/zephyr/commit/ec822ceed83b5008d4a28700fdacf2ff80020963"},{"name":"Fix commit 2bd5ea88c69b","tags":["patch"],"url":"https://github.com/zephyrproject-rtos/zephyr/commit/2bd5ea88c69bdd94fc5a9e6757b29e1de9903ef5"},{"name":"GHSA-ffxg-752w-mv9x","url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-ffxg-752w-mv9x"}],"title":"Bluetooth Classic AVDTP session reuse re-initializes a queued work item, corrupting the system work queue","x_generator":{"engine":"cvelib 1.8.0"}}},"cveMetadata":{"assignerOrgId":"e2e69745-5e70-4e92-8431-deb5529a81ad","assignerShortName":"zephyr","cveId":"CVE-2026-85036","datePublished":"2026-11-04T06:09:01.385Z","dateReserved":"2026-09-02T20:23:19.935Z","dateUpdated":"2026-11-04T06:09:01.385Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-11-04 06:17:06","lastModifiedDate":"2026-11-04 06:17:06","problem_types":["CWE-666","CWE-666 memory-safety"],"metrics":{"cvssMetricV31":[{"source":"vulnerabilities@zephyrproject.org","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","baseScore":5.7,"baseSeverity":"MEDIUM","attackVector":"ADJACENT_NETWORK","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":2.1,"impactScore":3.6}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"85036","Ordinal":"1","Title":"Bluetooth Classic AVDTP session reuse re-initializes a queued wo","CVE":"CVE-2026-85036","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"85036","Ordinal":"1","NoteData":"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.","Type":"Description","Title":"Bluetooth Classic AVDTP session reuse re-initializes a queued wo"}]}}}