{"id":"CVE-2026-89569","summary":"Bluetooth: RFCOMM: serialize security confirmation handling","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nBluetooth: RFCOMM: serialize security confirmation handling\n\nrfcomm_security_cfm() looks up a session on session_list and then walks\nits DLC list without holding rfcomm_mutex. Since RFCOMM session teardown\nuses rfcomm_mutex, krfcommd can close and free the same session and DLCs\nconcurrently:\n\n  hci_rx_work                    krfcommd\n  -----------                    ---------\n  rfcomm_session_get()\n                                 rfcomm_lock()\n                                 rfcomm_session_close()\n                                   rfcomm_dlc_unlink()\n                                   rfcomm_session_del()\n                                     kfree(s)\n                                 rfcomm_unlock()\n  walk s-\u003edlcs\n\nThe callback can then read a freed session list head and touch freed DLCs\nwhile updating their flags or timers.\n\nSerialize the session lookup and DLC traversal in rfcomm_security_cfm()\nwith rfcomm_mutex. This matches the existing RFCOMM session lifetime\nrules and prevents concurrent rfcomm_session_del() / rfcomm_dlc_unlink()\nfrom tearing the objects down while the callback is using them.\n\nKASAN reported:\n\n  BUG: KASAN: slab-use-after-free in rfcomm_security_cfm+0x41c/0x440\n  Read of size 8 at addr ffff888111fb3960 by task kworker/u17:1/89\n  Workqueue: hci0 hci_rx_work\n  Call Trace:\n   rfcomm_security_cfm+0x41c/0x440\n   hci_encrypt_cfm+0x139/0x590\n   hci_encrypt_change_evt+0x37b/0xc40\n   hci_event_packet+0x71b/0xb20\n   hci_rx_work+0x293/0x730\n  Allocated by task 69:\n   rfcomm_session_add+0x9e/0x2f0\n   rfcomm_run+0x44b/0x41e0\n  Freed by task 69:\n   kfree+0x131/0x3c0\n   rfcomm_session_del+0x188/0x220\n   rfcomm_run+0x1985/0x41e0","modified":"2026-09-13T03:47:19.349415382Z","published":"2026-09-11T19:44:38.838Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89569.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/1b7841ffad08e911e8c4b9470f3fa08423568940"},{"type":"WEB","url":"https://git.kernel.org/stable/c/759c185d0bbdb131357408f50b8735e04ed3caff"},{"type":"WEB","url":"https://git.kernel.org/stable/c/946d76db77ee5f922968ce558629ae47b381e3fc"},{"type":"WEB","url":"https://git.kernel.org/stable/c/fbf7961964a6e93360179f64712320ae9a1e9577"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/89xxx/CVE-2026-89569.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-89569"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"08c30aca9e698faddebd34f81e1196295f9dc063"},{"fixed":"1b7841ffad08e911e8c4b9470f3fa08423568940"},{"fixed":"946d76db77ee5f922968ce558629ae47b381e3fc"},{"fixed":"fbf7961964a6e93360179f64712320ae9a1e9577"},{"fixed":"759c185d0bbdb131357408f50b8735e04ed3caff"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89569.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"3.10.0"},{"fixed":"6.12.109"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.50"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.4"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-89569.json"}}],"schema_version":"1.9.0"}