CVE-2026-89569
Description
In the Linux kernel, the following vulnerability has been resolved: Bluetooth: RFCOMM: serialize security confirmation handling rfcomm_security_cfm() looks up a session on session_list and then walks its DLC list without holding rfcomm_mutex. Since RFCOMM session teardown uses rfcomm_mutex, krfcommd can close and free the same session and DLCs concurrently: hci_rx_work krfcommd ----------- --------- rfcomm_session_get() rfcomm_lock() rfcomm_session_close() rfcomm_dlc_unlink() rfcomm_session_del() kfree(s) rfcomm_unlock() walk s->dlcs The callback can then read a freed session list head and touch freed DLCs while updating their flags or timers. Serialize the session lookup and DLC traversal in rfcomm_security_cfm() with rfcomm_mutex. This matches the existing RFCOMM session lifetime rules and prevents concurrent rfcomm_session_del() / rfcomm_dlc_unlink() from tearing the objects down while the callback is using them. KASAN reported: BUG: KASAN: slab-use-after-free in rfcomm_security_cfm+0x41c/0x440 Read of size 8 at addr ffff888111fb3960 by task kworker/u17:1/89 Workqueue: hci0 hci_rx_work Call Trace: rfcomm_security_cfm+0x41c/0x440 hci_encrypt_cfm+0x139/0x590 hci_encrypt_change_evt+0x37b/0xc40 hci_event_packet+0x71b/0xb20 hci_rx_work+0x293/0x730 Allocated by task 69: rfcomm_session_add+0x9e/0x2f0 rfcomm_run+0x44b/0x41e0 Freed by task 69: kfree+0x131/0x3c0 rfcomm_session_del+0x188/0x220 rfcomm_run+0x1985/0x41e0
How to fix
- Linux Linux62ce8b33eb238cf18c15207332fbdc26d858f592, 3873f3449701b3dc98cba577923be6493598e7a1, 7ded3264106418c6456ccceaafd9fda596ce12c3, 82425b14f0fb22e46cfddc56d6465570f5ed0ce6, 1b7841ffad08e911e8c4b9470f3fa08423568940, 946d76db77ee5f922968ce558629ae47b381e3fc, fbf7961964a6e93360179f64712320ae9a1e9577, 759c185d0bbdb131357408f50b8735e04ed3caff or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| Linux Linux | 08c30aca9e698faddebd34f81e1196295f9dc063 ≤ v < 62ce8b33eb238cf18c15207332fbdc26d858f592, 08c30aca9e698faddebd34f81e1196295f9dc063 ≤ v < 3873f3449701b3dc98cba577923be6493598e7a1, 08c30aca9e698faddebd34f81e1196295f9dc063 ≤ v < 7ded3264106418c6456ccceaafd9fda596ce12c3, 08c30aca9e698faddebd34f81e1196295f9dc063 ≤ v < 82425b14f0fb22e46cfddc56d6465570f5ed0ce6, 08c30aca9e698faddebd34f81e1196295f9dc063 ≤ v < 1b7841ffad08e911e8c4b9470f3fa08423568940, 08c30aca9e698faddebd34f81e1196295f9dc063 ≤ v < 946d76db77ee5f922968ce558629ae47b381e3fc, 08c30aca9e698faddebd34f81e1196295f9dc063 ≤ v < fbf7961964a6e93360179f64712320ae9a1e9577, 08c30aca9e698faddebd34f81e1196295f9dc063 ≤ v < 759c185d0bbdb131357408f50b8735e04ed3caff, 3.10 | 62ce8b33eb238cf18c15207332fbdc26d858f592, 3873f3449701b3dc98cba577923be6493598e7a1, 7ded3264106418c6456ccceaafd9fda596ce12c3, 82425b14f0fb22e46cfddc56d6465570f5ed0ce6, 1b7841ffad08e911e8c4b9470f3fa08423568940, 946d76db77ee5f922968ce558629ae47b381e3fc, fbf7961964a6e93360179f64712320ae9a1e9577, 759c185d0bbdb131357408f50b8735e04ed3caff |
Check your version
Choose the product and enter the version you run to see whether it falls in the affected range.
Attack Surface Management
See the assets tied to your domains, the technologies they run and known vulnerabilities in one list.