{"cve":"CVE-2025-68304","nvd":{"published":"2025-12-16T16:16:09.930","modified":"2026-10-15T22:19:11.733","status":"Deferred","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: hci_core: lookup hci_conn on RX path on protocol side\n\nThe hdev lock/lookup/unlock/use pattern in the packet RX path doesn't\nensure hci_conn* is not concurrently modified/deleted. This locking\nappears to be leftover from before conn_hash started using RCU\ncommit bf4c63252490b (\"Bluetooth: convert conn hash to RCU\")\nand not clear if it had purpose since then.\n\nCurrently, there are code paths that delete hci_conn* from elsewhere\nthan the ordered hdev->workqueue where the RX work runs in. E.g.\ncommit 5af1f84ed13a (\"Bluetooth: hci_sync: Fix UAF on hci_abort_conn_sync\")\nintroduced some of these, and there probably were a few others before\nit.  It's better to do the locking so that even if these run\nconcurrently no UAF is possible.\n\nMove the lookup of hci_conn and associated socket-specific conn to\nprotocol recv handlers, and do them within a single critical section\nto cover hci_conn* usage and lookup.\n\nsyzkaller has reported a crash that appears to be this issue:\n\n    [Task hdev->workqueue]          [Task 2]\n                                    hci_disconnect_all_sync\n    l2cap_recv_acldata(hcon)\n                                      hci_conn_get(hcon)\n                                      hci_abort_conn_sync(hcon)\n                                        hci_dev_lock\n      hci_dev_lock\n                                        hci_conn_del(hcon)\n      v-------------------------------- hci_dev_unlock\n                                      hci_conn_put(hcon)\n      conn = hcon->l2cap_data (UAF)","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":8.8},"cwes":[],"references":["https://git.kernel.org/stable/c/79a2d4678ba90bdba577dc3af88cc900d6dcd5ee","https://git.kernel.org/stable/c/ec74cdf77310c43b01b83ee898a9bd4b4b0b8e93"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:17:07.138532058+00:00"},"epss":{"cve":"CVE-2025-68304","score":0.00233,"percentile":0.14019,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}