cbcvebase.
CVE-2025-39985
published 2025-10-15

CVE-2025-39985: 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…

PriorityP345high7.8CVSS 3.1
AVLACLPRLUINSUCHIHAH
EPSS
0.16%
6.1th percentile
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.

Affected

30 ranges· showing 25
VendorProductVersion rangeFixed in
debianlinux< linux 6.1.158-1 (bookworm)linux 6.1.158-1 (bookworm)
debianlinux-6.1< linux 6.1.158-1 (bookworm)linux 6.1.158-1 (bookworm)
linuxlinux
linuxlinux>= 51f3baad7de943780ce0c17bd7975df567dd6e14 < 0fa9303c4b9493727e0d3a6ac3729300e30139300fa9303c4b9493727e0d3a6ac3729300e3013930
linuxlinux>= 51f3baad7de943780ce0c17bd7975df567dd6e14 < 37aed407496bf6de8910e588edb04d2435fa701137aed407496bf6de8910e588edb04d2435fa7011
linuxlinux>= 51f3baad7de943780ce0c17bd7975df567dd6e14 < 6eec67bfb25637f9b51e584cf59ddace59925bc86eec67bfb25637f9b51e584cf59ddace59925bc8
linuxlinux>= 51f3baad7de943780ce0c17bd7975df567dd6e14 < ca4e51359608e1f29bf1f2c33c3ddf775b6b7ed1ca4e51359608e1f29bf1f2c33c3ddf775b6b7ed1
linuxlinux>= 51f3baad7de943780ce0c17bd7975df567dd6e14 < 3664ae91b26d1fd7e4cee9cde17301361f4c89d53664ae91b26d1fd7e4cee9cde17301361f4c89d5
linuxlinux>= 51f3baad7de943780ce0c17bd7975df567dd6e14 < 6b9fb82df8868dbe9ffea5874b8d35f951faedbb6b9fb82df8868dbe9ffea5874b8d35f951faedbb
linuxlinux>= 51f3baad7de943780ce0c17bd7975df567dd6e14 < b638c3fb0f163e69785ceddb3b434a9437878becb638c3fb0f163e69785ceddb3b434a9437878bec
linuxlinux>= 51f3baad7de943780ce0c17bd7975df567dd6e14 < 17c8d794527f01def0d1c8b7dc2d7b8d34fed0e617c8d794527f01def0d1c8b7dc2d7b8d34fed0e6
linuxlinux_kernel>= 0 < 5.10.247-15.10.247-1
linuxlinux_kernel>= 0 < 6.1.158-16.1.158-1
linuxlinux_kernel>= 0 < 6.12.57-16.12.57-1
linuxlinux_kernel>= 0 < 6.16.10-16.16.10-1
linuxlinux_kernel>= 0 < 5.15.0-170.1805.15.0-170.180
linuxlinux_kernel>= 0 < 6.8.0-106.1066.8.0-106.106
linuxlinux_kernel>= 4.12.0 < 5.4.3005.4.300
linuxlinux_kernel>= 5.11.0 < 5.15.1945.15.194
linuxlinux_kernel>= 5.16.0 < 6.1.1556.1.155
linuxlinux_kernel>= 5.5.0 < 5.10.2455.10.245
linuxlinux_kernel>= 6.13.0 < 6.16.106.16.10
linuxlinux_kernel>= 6.2.0 < 6.6.1096.6.109
linuxlinux_kernel>= 6.7.0 < 6.12.506.12.50
msrcazl3_kernel_6.6.104.2-4_on_azure_linux_3.0

CVSS provenance

nvdv3.17.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
osv7.8HIGH
vendor_msrc9.8CRITICAL
vendor_ubuntu7.8HIGH
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