{"id":"CVE-2026-11368","summary":"Use-after-free in Bluetooth host ATT TX completion on disconnect mid-transfer","details":"The Bluetooth host ATT layer (subsys/bluetooth/host/att.c) associates each in-flight ATT TX buffer with its owning channel via the static tx_meta_data_storage[] array (data-\u003eatt_chan = chan). When a buffer's last reference is dropped, its net-buf destroy callback defers the completion handling to the system workqueue (att_tx_destroy -\u003e att_tx_destroy_work_handler -\u003e att_on_sent_cb -\u003e bt_att_sent), where bt_att_sent dereferences the channel and its ATT context (sys_slist_get(&att-\u003ereqs)).\n\nWhen a peer disconnects while an ATT PDU (a server notification/indication or any response) is still in flight in the controller TX path, L2CAP tears the channel down in l2cap_chan_del(): it runs the disconnected callback and then the released callback (bt_att_released), which frees the channel slab slot. Because the in-flight buffer is held by the connection TX path rather than the channel's own queue, its deferred destroy work can run after the channel has been freed. The att_on_sent_cb guard intended to drop the stale callback itself dereferences meta-\u003eatt_chan, which is now a dangling pointer into a freed (and possibly reused) slab slot.\n\nA remote peer with an ATT connection can drive this by disconnecting during routine ATT traffic; no pairing or user interaction is required to reach the ATT bearer. The result is a use-after-free read/write of freed channel memory, reliably crashing the Bluetooth host (denial of service) and, because the channel slab slot may be reused, potentially corrupting live memory.\n\nThe fix makes bt_att_released() NULL the att_chan field of every tx_meta_data_storage[] entry still referencing the channel before freeing it, so the deferred guard observes a NULL pointer and drops the callback. Teardown and the destroy work both run on the cooperative system workqueue, so the array update is serialized and needs no lock.","aliases":["GHSA-85vg-gwc4-77g7"],"modified":"2026-10-28T11:02:17.729729459Z","published":"2026-08-04T14:23:28.866Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/11xxx/CVE-2026-11368.json","cna_assigner":"zephyr","cwe_ids":["CWE-416"]},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/11xxx/CVE-2026-11368.json"},{"type":"ADVISORY","url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-85vg-gwc4-77g7"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-11368"},{"type":"FIX","url":"https://github.com/zephyrproject-rtos/zephyr/commit/dfdea9bad8d9b5b31c125e97fcffb549f2217caa"},{"type":"PACKAGE","url":"https://github.com/zephyrproject-rtos/zephyr"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/zephyrproject-rtos/zephyr","events":[{"introduced":"684c9e8f32e4373a21098559f748f06915f950c9"},{"fixed":"dccb09599635bdff17633fa7e9dab014b91dce90"},{"fixed":"dfdea9bad8d9b5b31c125e97fcffb549f2217caa"}],"database_specific":{"extracted_events":[{"strategy":"StandardRange","range":[{"introduced":"4.4.0"},{"fixed":"4.4.2"}],"source":"AFFECTED_FIELD"},{"source":"REFERENCES_COMMIT","range":[{"fixed":"dfdea9bad8d9b5b31c125e97fcffb549f2217caa"}]}]}}],"versions":["v4.4.2-rc1","v4.4.1","v4.4.1-rc1","v4.4.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-11368.json","vanir_signatures":[{"signature_version":"v1","source":"https://github.com/zephyrproject-rtos/zephyr/commit/dfdea9bad8d9b5b31c125e97fcffb549f2217caa","target":{"file":"subsys/bluetooth/host/att.c"},"deprecated":false,"digest":{"threshold":0.9,"line_hashes":["85345839144928522256832224544957925061","68015516838401139367547573425467212601","239969337071624576282072356890530064731"]},"id":"CVE-2026-11368-939afea7","signature_type":"Line"},{"signature_version":"v1","source":"https://github.com/zephyrproject-rtos/zephyr/commit/dfdea9bad8d9b5b31c125e97fcffb549f2217caa","target":{"function":"bt_att_released","file":"subsys/bluetooth/host/att.c"},"deprecated":false,"digest":{"function_hash":"227444997735229437439173149438888094354","length":154},"id":"CVE-2026-11368-c6991694","signature_type":"Function"}],"vanir_signatures_modified":"2026-10-28T11:02:17Z"}}],"schema_version":"1.9.2","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H"}]}