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CVE-2025-39985— can: mcba_usb: populate ndo_change_mtu() to prevent buffer overflow

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mcba_usb驱动未实现ndo_change_mtu函数，可能导致缓冲区溢出攻击。

CVSS 7.8 · High EPSS 0.18% · P7

Affected Version Matrix 18

VendorProduct Version RangeStatus
Linux Linux 51f3baad7de943780ce0c17bd7975df567dd6e14< 0fa9303c4b9493727e0d3a6ac3729300e3013930 affected
51f3baad7de943780ce0c17bd7975df567dd6e14< 37aed407496bf6de8910e588edb04d2435fa7011 affected
51f3baad7de943780ce0c17bd7975df567dd6e14< 6eec67bfb25637f9b51e584cf59ddace59925bc8 affected
51f3baad7de943780ce0c17bd7975df567dd6e14< ca4e51359608e1f29bf1f2c33c3ddf775b6b7ed1 affected
51f3baad7de943780ce0c17bd7975df567dd6e14< 3664ae91b26d1fd7e4cee9cde17301361f4c89d5 affected
51f3baad7de943780ce0c17bd7975df567dd6e14< 6b9fb82df8868dbe9ffea5874b8d35f951faedbb affected
51f3baad7de943780ce0c17bd7975df567dd6e14< b638c3fb0f163e69785ceddb3b434a9437878bec affected
51f3baad7de943780ce0c17bd7975df567dd6e14< 17c8d794527f01def0d1c8b7dc2d7b8d34fed0e6 affected
… +10 more rows
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I. Basic Information for CVE-2025-39985

Vulnerability Information
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Vulnerability Title
can: mcba_usb: populate ndo_change_mtu() to prevent buffer overflow
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: can: mcba_usb: populate ndo_change_mtu() to prevent buffer overflow Sending an PF_PACKET allows to bypass the CAN framework logic and to directly reach the xmit() function of a CAN driver. The only check which is performed by the PF_PACKET framework is to make sure that skb->len fits the interface's MTU. Unfortunately, because the mcba_usb driver does not populate its net_device_ops->ndo_change_mtu(), it is possible for an attacker to configure an invalid MTU by doing, for example: $ ip link set can0 mtu 9999 After doing so, the attacker could open a PF_PACKET socket using the ETH_P_CANXL protocol: socket(PF_PACKET, SOCK_RAW, htons(ETH_P_CANXL)) to inject a malicious CAN XL frames. For example: struct canxl_frame frame = { .flags = 0xff, .len = 2048, }; The CAN drivers' xmit() function are calling can_dev_dropped_skb() to check that the skb is valid, unfortunately under above conditions, the malicious packet is able to go through can_dev_dropped_skb() checks: 1. the skb->protocol is set to ETH_P_CANXL which is valid (the function does not check the actual device capabilities). 2. the length is a valid CAN XL length. And so, mcba_usb_start_xmit() receives a CAN XL frame which it is not able to correctly handle and will thus misinterpret it as a CAN frame. This can result in a buffer overflow. The driver will consume cf->len as-is with no further checks on these lines: usb_msg.dlc = cf->len; memcpy(usb_msg.data, cf->data, usb_msg.dlc); Here, cf->len corresponds to the flags field of the CAN XL frame. In our previous example, we set canxl_frame->flags to 0xff. Because the maximum expected length is 8, a buffer overflow of 247 bytes occurs! Populate net_device_ops->ndo_change_mtu() to ensure that the interface's MTU can not be set to anything bigger than CAN_MTU. By fixing the root cause, this prevents the buffer overflow.
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mcba_usb驱动未实现ndo_change_mtu函数，可能导致缓冲区溢出攻击。
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 51f3baad7de943780ce0c17bd7975df567dd6e14 ~ 0fa9303c4b9493727e0d3a6ac3729300e3013930 -
Linux Linux 4.12 -

II. Public POCs for CVE-2025-39985

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III. Intelligence Information for CVE-2025-39985

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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-2025-39986 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
CVE-2025-39990 7.8 HIGH bpf: Check the helper function is valid in get_helper_proto

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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