In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: RFCOMM: Fix session UAF in set_termios
rfcomm_tty_set_termios() tests dlc->session without rfcomm_mutex and
later passes the pointer to rfcomm_send_rpn(). The latter dereferences
both session->initiator and session->sock. Meanwhile, krfcommd can
unlink the DLC and free the session while holding rfcomm_mutex.
The race can proceed as follows:
TTY ioctl task krfcommd
-------------- --------
load dlc->session
enter rfcomm_send_rpn()
lock rfcomm_mutex
clear dlc->session
free session
unlock rfcomm_mutex
read session->initiator
KASAN reported:
BUG: KASAN: slab-use-after-free in rfcomm_send_rpn+0x297/0x2a0
Read of size 4 at addr ffff88810012a850 by task poc/92
Call Trace:
rfcomm_send_rpn+0x297/0x2a0
rfcomm_tty_set_termios+0x50d/0x850
tty_set_termios+0x596/0x950
set_termios+0x46a/0x6e0
tty_mode_ioctl+0x152/0xbd0
tty_ioctl+0x915/0x1240
__x64_sys_ioctl+0x134/0x1c0
Allocated by task 92:
rfcomm_session_add+0x9e/0x2e0
rfcomm_dlc_open+0x8b1/0xe00
rfcomm_dev_activate+0x85/0x1a0
rfcomm_tty_open+0x90/0x280
Freed by task 68:
kfree+0x131/0x3c0
rfcomm_session_del+0x119/0x180
rfcomm_run+0x737/0x4710
Add rfcomm_dlc_send_rpn(), which holds rfcomm_mutex while it verifies
that the DLC is still attached and sends the RPN frame. Have the TTY
path use the helper and drop its unlocked session check. This keeps the
session valid through both the frame construction and socket send.
Metrics
Affected Vendors & Products
References
History
Mon, 10 Aug 2026 14:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-122 |
Mon, 10 Aug 2026 12:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: Bluetooth: RFCOMM: Fix session UAF in set_termios rfcomm_tty_set_termios() tests dlc->session without rfcomm_mutex and later passes the pointer to rfcomm_send_rpn(). The latter dereferences both session->initiator and session->sock. Meanwhile, krfcommd can unlink the DLC and free the session while holding rfcomm_mutex. The race can proceed as follows: TTY ioctl task krfcommd -------------- -------- load dlc->session enter rfcomm_send_rpn() lock rfcomm_mutex clear dlc->session free session unlock rfcomm_mutex read session->initiator KASAN reported: BUG: KASAN: slab-use-after-free in rfcomm_send_rpn+0x297/0x2a0 Read of size 4 at addr ffff88810012a850 by task poc/92 Call Trace: rfcomm_send_rpn+0x297/0x2a0 rfcomm_tty_set_termios+0x50d/0x850 tty_set_termios+0x596/0x950 set_termios+0x46a/0x6e0 tty_mode_ioctl+0x152/0xbd0 tty_ioctl+0x915/0x1240 __x64_sys_ioctl+0x134/0x1c0 Allocated by task 92: rfcomm_session_add+0x9e/0x2e0 rfcomm_dlc_open+0x8b1/0xe00 rfcomm_dev_activate+0x85/0x1a0 rfcomm_tty_open+0x90/0x280 Freed by task 68: kfree+0x131/0x3c0 rfcomm_session_del+0x119/0x180 rfcomm_run+0x737/0x4710 Add rfcomm_dlc_send_rpn(), which holds rfcomm_mutex while it verifies that the DLC is still attached and sends the RPN frame. Have the TTY path use the helper and drop its unlocked session check. This keeps the session valid through both the frame construction and socket send. | |
| Title | Bluetooth: RFCOMM: Fix session UAF in set_termios | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
|
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-08-10T12:00:00.521Z
Reserved: 2026-07-30T09:28:09.373Z
Link: CVE-2026-68188
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OpenCVE Enrichment
Updated: 2026-08-10T17:00:03Z