CVE-2025-38117 in Linux
Summary
by MITRE • 07/03/2025
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: MGMT: Protect mgmt_pending list with its own lock
This uses a mutex to protect from concurrent access of mgmt_pending list which can cause crashes like:
================================================================== BUG: KASAN: slab-use-after-free in hci_sock_get_channel+0x60/0x68 net/bluetooth/hci_sock.c:91 Read of size 2 at addr ffff0000c48885b2 by task syz.4.334/7318
CPU: 0 UID: 0 PID: 7318 Comm: syz.4.334 Not tainted 6.15.0-rc7-syzkaller-g187899f4124a #0 PREEMPT Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call trace: show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:466 (C) __dump_stack+0x30/0x40 lib/dump_stack.c:94 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120 print_address_description+0xa8/0x254 mm/kasan/report.c:408 print_report+0x68/0x84 mm/kasan/report.c:521 kasan_report+0xb0/0x110 mm/kasan/report.c:634 __asan_report_load2_noabort+0x20/0x2c mm/kasan/report_generic.c:379 hci_sock_get_channel+0x60/0x68 net/bluetooth/hci_sock.c:91 mgmt_pending_find+0x7c/0x140 net/bluetooth/mgmt_util.c:223 pending_find net/bluetooth/mgmt.c:947 [inline]
remove_adv_monitor+0x44/0x1a4 net/bluetooth/mgmt.c:5445 hci_mgmt_cmd+0x780/0xc00 net/bluetooth/hci_sock.c:1712 hci_sock_sendmsg+0x544/0xbb0 net/bluetooth/hci_sock.c:1832 sock_sendmsg_nosec net/socket.c:712 [inline]
__sock_sendmsg net/socket.c:727 [inline]
sock_write_iter+0x25c/0x378 net/socket.c:1131 new_sync_write fs/read_write.c:591 [inline]
vfs_write+0x62c/0x97c fs/read_write.c:684 ksys_write+0x120/0x210 fs/read_write.c:736 __do_sys_write fs/read_write.c:747 [inline]
__se_sys_write fs/read_write.c:744 [inline]
__arm64_sys_write+0x7c/0x90 fs/read_write.c:744 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x58/0x17c arch/arm64/kernel/entry-common.c:767 el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:786 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600
Allocated by task 7037: kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x40/0x78 mm/kasan/common.c:68 kasan_save_alloc_info+0x44/0x54 mm/kasan/generic.c:562 poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
__kasan_kmalloc+0x9c/0xb4 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline]
__do_kmalloc_node mm/slub.c:4327 [inline]
__kmalloc_noprof+0x2fc/0x4c8 mm/slub.c:4339 kmalloc_noprof include/linux/slab.h:909 [inline]
sk_prot_alloc+0xc4/0x1f0 net/core/sock.c:2198 sk_alloc+0x44/0x3ac net/core/sock.c:2254 bt_sock_alloc+0x4c/0x300 net/bluetooth/af_bluetooth.c:148 hci_sock_create+0xa8/0x194 net/bluetooth/hci_sock.c:2202 bt_sock_create+0x14c/0x24c net/bluetooth/af_bluetooth.c:132 __sock_create+0x43c/0x91c net/socket.c:1541 sock_create net/socket.c:1599 [inline]
__sys_socket_create net/socket.c:1636 [inline]
__sys_socket+0xd4/0x1c0 net/socket.c:1683 __do_sys_socket net/socket.c:1697 [inline]
__se_sys_socket net/socket.c:1695 [inline]
__arm64_sys_socket+0x7c/0x94 net/socket.c:1695 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x58/0x17c arch/arm64/kernel/entry-common.c:767 el0t_64_sync_handler+0x78/0x108 arch/arm64/kernel/entry-common.c:786 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600
Freed by task 6607: kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x40/0x78 mm/kasan/common.c:68 kasan_save_free_info+0x58/0x70 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:247 [inline]
__kasan_slab_free+0x68/0x88 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline
---truncated---
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Analysis
by VulDB Data Team • 04/18/2026
The vulnerability CVE-2025-38117 affects the Linux kernel's Bluetooth subsystem, specifically within the management socket implementation. This flaw arises from insufficient synchronization mechanisms protecting the mgmt_pending list, which is used to track pending management commands in the Bluetooth stack. The lack of proper locking allows for concurrent access to this data structure, leading to potential use-after-free conditions and system crashes. The issue manifests when multiple threads attempt to access or modify the mgmt_pending list simultaneously without adequate mutual exclusion, creating a race condition that can result in memory corruption.
The technical root cause involves the mgmt_pending list being accessed through functions such as hci_sock_get_channel and mgmt_pending_find without proper locking. When a freed memory object is subsequently accessed, it triggers a KASAN (Kernel Address Sanitizer) error indicating a slab-use-after-free condition. The stack trace shows the crash originates from hci_sock_get_channel attempting to read from memory that was previously freed by another thread, demonstrating the classic symptoms of a race condition in concurrent programming. This vulnerability directly relates to CWE-362, which describes concurrent execution using shared data structures without proper synchronization.
The operational impact of this vulnerability is significant as it can lead to system instability, potential denial of service, and in some cases, arbitrary code execution. An attacker could exploit this by crafting specific Bluetooth management commands that trigger concurrent access patterns to the vulnerable data structure. The crash occurs during socket operations involving Bluetooth management commands, particularly when dealing with advertising monitors and pending command tracking. Systems running vulnerable kernel versions are at risk when handling Bluetooth traffic, especially in environments where multiple processes or threads interact with Bluetooth management interfaces simultaneously.
Mitigation strategies for this vulnerability include applying the official kernel patch that introduces a dedicated mutex to protect the mgmt_pending list, ensuring exclusive access during list modifications. System administrators should prioritize updating to kernel versions that contain the fix, particularly those incorporating the Bluetooth management lock protection. Additional defensive measures include monitoring for unusual Bluetooth socket behavior and implementing proper access controls for Bluetooth interfaces. Organizations should also consider deploying kernel hardening techniques such as stack canaries and KASAN instrumentation to detect similar race conditions. This vulnerability aligns with ATT&CK technique T1059.007 (Command and Scripting Interpreter: PowerShell) in the context of kernel-level exploitation, though the actual exploitation would require specific conditions to trigger the race condition effectively.