{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-19940", "assignerOrgId": "e2e69745-5e70-4e92-8431-deb5529a81ad", "state": "PUBLISHED", "assignerShortName": "zephyr", "dateReserved": "2026-08-15T13:31:23.585Z", "datePublished": "2026-10-13T16:40:10.541Z", "dateUpdated": "2026-10-13T16:40:10.541Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "e2e69745-5e70-4e92-8431-deb5529a81ad", "shortName": "zephyr", "dateUpdated": "2026-10-13T16:40:10.541Z"}, "title": "Bluetooth HFP AG reuses a connection slot while a delayable work item is still armed, corrupting kernel timeout bookkeeping", "descriptions": [{"lang": "en", "value": "The Bluetooth Classic Hands-Free Profile Audio Gateway implementation in subsys/bluetooth/host/classic/hfp_ag.c keeps its struct bt_hfp_ag objects in a static pool indexed by ACL connection index. On link teardown, hfp_ag_disconnected() cancels ag->tx_work and the per-call work items and then clears ag->acl_conn, which marks the pool slot as free \u2014 but it leaves ag->ongoing_call_work (and ag->slc_work) untouched. The next connection that lands on the same slot enters hfp_ag_create(), whose only occupancy test is ag->acl_conn, and immediately executes memset(ag, 0, sizeof(struct bt_hfp_ag)) followed by k_work_init_delayable(). Zeroing and re-initialising a k_work_delayable whose struct _timeout node is still linked into the kernel timeout list leaves the kernel holding a reference to a node with NULL prev/next links.\n\nag->ongoing_call_work is armed by the remote peer: when a Hands-Free unit sends AT+CIND? during Service Level Connection establishment and the application provides the asynchronous get_ongoing_call callback, the AG schedules the work for CONFIG_BT_HFP_AG_GET_ONGOING_CALL_TIMEOUT milliseconds (default 10000). The timer is cancelled only if the application answers in time via bt_hfp_ag_ongoing_calls(). A peer that sends AT+CIND?, then disconnects the HFP RFCOMM DLC, then immediately re-opens it on the same ACL link, reuses the same pool slot deterministically while the timeout is still pending \u2014 the AG's RFCOMM server accept path (hfp_ag_accept()) calls hfp_ag_create() directly, so the remote side drives both teardown and re-creation.\n\nThe result is corruption of the kernel's timeout list: sys_dlist_remove() on the zeroed node performs writes through NULL pointers from the clock-announce path, and rescheduling the re-initialised work re-inserts a node the list already references, creating a cycle that the announce loop walks with interrupts locked. The observable impact is a fault or hang of the whole system, i.e. a denial of service reachable from Bluetooth radio range; no attacker-controlled data is written, so this does not by itself yield code execution. Exposure is limited to builds with CONFIG_BT_HFP_AG (marked experimental and disabled by default) whose application implements the asynchronous get_ongoing_call callback."}], "affected": [{"vendor": "zephyrproject", "product": "zephyr", "collectionURL": "https://github.com/zephyrproject-rtos/zephyr", "packageName": "zephyr", "defaultStatus": "unaffected", "programFiles": ["subsys/bluetooth/host/classic/hfp_ag.c"], "programRoutines": [{"name": "hfp_ag_create"}, {"name": "hfp_ag_disconnected"}], "versions": [{"version": "4.2.0", "status": "affected", "versionType": "semver", "lessThanOrEqual": "4.4.2"}]}], "references": [{"url": "https://github.com/zephyrproject-rtos/zephyr/commit/204c36b896fe8d68ca3cb3d00216f245f91d14be", "name": "Fix commit", "tags": ["patch"]}, {"url": "https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-v47w-8959-rx62", "name": "GHSA-v47w-8959-rx62"}], "metrics": [{"format": "CVSS", "cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 6.5, "baseSeverity": "MEDIUM"}}], "problemTypes": [{"descriptions": [{"lang": "en", "description": "use-after-free", "cweId": "CWE-416", "type": "CWE"}]}], "x_generator": {"engine": "cvelib 1.8.0"}}}}

{}

{"affected": [{"affectedData": [{"collectionURL": "https://github.com/zephyrproject-rtos/zephyr", "defaultStatus": "unaffected", "packageName": "zephyr", "product": "zephyr", "programFiles": ["subsys/bluetooth/host/classic/hfp_ag.c"], "programRoutines": [{"name": "hfp_ag_create"}, {"name": "hfp_ag_disconnected"}], "vendor": "zephyrproject", "versions": [{"lessThanOrEqual": "4.4.2", "status": "affected", "version": "4.2.0", "versionType": "semver"}]}], "source": "[email protected]"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "The Bluetooth Classic Hands-Free Profile Audio Gateway implementation in subsys/bluetooth/host/classic/hfp_ag.c keeps its struct bt_hfp_ag objects in a static pool indexed by ACL connection index. On link teardown, hfp_ag_disconnected() cancels ag->tx_work and the per-call work items and then clears ag->acl_conn, which marks the pool slot as free \u2014 but it leaves ag->ongoing_call_work (and ag->slc_work) untouched. The next connection that lands on the same slot enters hfp_ag_create(), whose only occupancy test is ag->acl_conn, and immediately executes memset(ag, 0, sizeof(struct bt_hfp_ag)) followed by k_work_init_delayable(). Zeroing and re-initialising a k_work_delayable whose struct _timeout node is still linked into the kernel timeout list leaves the kernel holding a reference to a node with NULL prev/next links.\n\nag->ongoing_call_work is armed by the remote peer: when a Hands-Free unit sends AT+CIND? during Service Level Connection establishment and the application provides the asynchronous get_ongoing_call callback, the AG schedules the work for CONFIG_BT_HFP_AG_GET_ONGOING_CALL_TIMEOUT milliseconds (default 10000). The timer is cancelled only if the application answers in time via bt_hfp_ag_ongoing_calls(). A peer that sends AT+CIND?, then disconnects the HFP RFCOMM DLC, then immediately re-opens it on the same ACL link, reuses the same pool slot deterministically while the timeout is still pending \u2014 the AG's RFCOMM server accept path (hfp_ag_accept()) calls hfp_ag_create() directly, so the remote side drives both teardown and re-creation.\n\nThe result is corruption of the kernel's timeout list: sys_dlist_remove() on the zeroed node performs writes through NULL pointers from the clock-announce path, and rescheduling the re-initialised work re-inserts a node the list already references, creating a cycle that the announce loop walks with interrupts locked. The observable impact is a fault or hang of the whole system, i.e. a denial of service reachable from Bluetooth radio range; no attacker-controlled data is written, so this does not by itself yield code execution. Exposure is limited to builds with CONFIG_BT_HFP_AG (marked experimental and disabled by default) whose application implements the asynchronous get_ongoing_call callback."}], "id": "CVE-2026-19940", "lastModified": "2026-10-13T17:17:40.107", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "ADJACENT_NETWORK", "availabilityImpact": "HIGH", "baseScore": 6.5, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 3.6, "source": "[email protected]", "type": "Secondary"}]}, "published": "2026-10-13T17:17:40.107", "references": [{"source": "[email protected]", "url": "https://github.com/zephyrproject-rtos/zephyr/commit/204c36b896fe8d68ca3cb3d00216f245f91d14be"}, {"source": "[email protected]", "url": "https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-v47w-8959-rx62"}], "sourceIdentifier": "[email protected]", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-416"}], "source": "[email protected]", "type": "Secondary"}]}

{}

{}