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CVE-2025-39993— media: rc: fix races with imon_disconnect()

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于imon_disconnect函数中存在竞争条件，可能导致释放后重用。

CVSS 7.8 · High EPSS 0.16% · P4

Affected Version Matrix 20

VendorProduct Version RangeStatus
Linux Linux 21677cfc562a27e099719d413287bc8d1d24deb7< 9348976003e39754af344949579e824a0a210fc4 affected
21677cfc562a27e099719d413287bc8d1d24deb7< b03fac6e2a38331faf8510b480becfa90cea1c9f affected
21677cfc562a27e099719d413287bc8d1d24deb7< 71c52b073922d05e79e6de7fc7f5f38f927929a4 affected
21677cfc562a27e099719d413287bc8d1d24deb7< 71096a6161a25e84acddb89a9d77f138502d26ab affected
21677cfc562a27e099719d413287bc8d1d24deb7< 71da40648741d15b302700b68973fe8b382aef3c affected
21677cfc562a27e099719d413287bc8d1d24deb7< fd5d3e6b149ec8cce045d86a2b5e3664d6b32ba5 affected
21677cfc562a27e099719d413287bc8d1d24deb7< d9f6ce99624a41c3bcb29a8d7d79b800665229dd affected
21677cfc562a27e099719d413287bc8d1d24deb7< 2e7fd93b9cc565b839bc55a6662475718963e156 affected
… +12 more rows
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I. Basic Information for CVE-2025-39993

Vulnerability Information
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Vulnerability Title
media: rc: fix races with imon_disconnect()
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: media: rc: fix races with imon_disconnect() Syzbot reports a KASAN issue as below: BUG: KASAN: use-after-free in __create_pipe include/linux/usb.h:1945 [inline] BUG: KASAN: use-after-free in send_packet+0xa2d/0xbc0 drivers/media/rc/imon.c:627 Read of size 4 at addr ffff8880256fb000 by task syz-executor314/4465 CPU: 2 PID: 4465 Comm: syz-executor314 Not tainted 6.0.0-rc1-syzkaller #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:317 [inline] print_report.cold+0x2ba/0x6e9 mm/kasan/report.c:433 kasan_report+0xb1/0x1e0 mm/kasan/report.c:495 __create_pipe include/linux/usb.h:1945 [inline] send_packet+0xa2d/0xbc0 drivers/media/rc/imon.c:627 vfd_write+0x2d9/0x550 drivers/media/rc/imon.c:991 vfs_write+0x2d7/0xdd0 fs/read_write.c:576 ksys_write+0x127/0x250 fs/read_write.c:631 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd The iMON driver improperly releases the usb_device reference in imon_disconnect without coordinating with active users of the device. Specifically, the fields usbdev_intf0 and usbdev_intf1 are not protected by the users counter (ictx->users). During probe, imon_init_intf0 or imon_init_intf1 increments the usb_device reference count depending on the interface. However, during disconnect, usb_put_dev is called unconditionally, regardless of actual usage. As a result, if vfd_write or other operations are still in progress after disconnect, this can lead to a use-after-free of the usb_device pointer. Thread 1 vfd_write Thread 2 imon_disconnect ... if usb_put_dev(ictx->usbdev_intf0) else usb_put_dev(ictx->usbdev_intf1) ... while send_packet if pipe = usb_sndintpipe( ictx->usbdev_intf0) UAF else pipe = usb_sndctrlpipe( ictx->usbdev_intf0, 0) UAF Guard access to usbdev_intf0 and usbdev_intf1 after disconnect by checking ictx->disconnected in all writer paths. Add early return with -ENODEV in send_packet(), vfd_write(), lcd_write() and display_open() if the device is no longer present. Set and read ictx->disconnected under ictx->lock to ensure memory synchronization. Acquire the lock in imon_disconnect() before setting the flag to synchronize with any ongoing operations. Ensure writers exit early and safely after disconnect before the USB core proceeds with cleanup. Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于imon_disconnect函数中存在竞争条件，可能导致释放后重用。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 21677cfc562a27e099719d413287bc8d1d24deb7 ~ 9348976003e39754af344949579e824a0a210fc4 -
Linux Linux 2.6.35 -

II. Public POCs for CVE-2025-39993

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III. Intelligence Information for CVE-2025-39993

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Patches & Fixes for CVE-2025-39993 (2)

Same Patch Batch · Linux · 2025-10-15 · 34 CVEs total

CVE-2025-39975 9.8 CRITICAL smb: client: fix wrong index reference in smb2_compound_op()
CVE-2025-40000 8.8 HIGH wifi: rtw89: fix use-after-free in rtw89_core_tx_kick_off_and_wait()
CVE-2025-39969 8.8 HIGH i40e: fix validation of VF state in get resources
CVE-2025-39971 8.8 HIGH i40e: fix idx validation in config queues msg
CVE-2025-39970 8.8 HIGH i40e: fix input validation logic for action_meta
CVE-2025-39972 8.8 HIGH i40e: fix idx validation in i40e_validate_queue_map
CVE-2025-39973 8.8 HIGH i40e: add validation for ring_len param
CVE-2025-39983 8.8 HIGH Bluetooth: hci_event: Fix UAF in hci_conn_tx_dequeue
CVE-2025-39982 8.8 HIGH Bluetooth: hci_event: Fix UAF in hci_acl_create_conn_sync
CVE-2025-39966 7.8 HIGH iommufd: Fix race during abort for file descriptors
CVE-2025-39967 7.8 HIGH fbcon: fix integer overflow in fbcon_do_set_font
CVE-2025-39976 7.8 HIGH futex: Use correct exit on failure from futex_hash_allocate_default()
CVE-2025-39977 7.8 HIGH futex: Prevent use-after-free during requeue-PI
CVE-2025-39978 7.8 HIGH octeontx2-pf: Fix potential use after free in otx2_tc_add_flow()
CVE-2025-39979 7.8 HIGH net/mlx5: fs, fix UAF in flow counter release
CVE-2025-39981 7.8 HIGH Bluetooth: MGMT: Fix possible UAFs
CVE-2025-39985 7.8 HIGH can: mcba_usb: populate ndo_change_mtu() to prevent buffer overflow
CVE-2025-39986 7.8 HIGH can: sun4i_can: populate ndo_change_mtu() to prevent buffer overflow
CVE-2025-39987 7.8 HIGH can: hi311x: populate ndo_change_mtu() to prevent buffer overflow
CVE-2025-39988 7.8 HIGH can: etas_es58x: populate ndo_change_mtu() to prevent buffer overflow

Showing top 20 of 34 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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