CVE-2025-38229

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

media: cxusb: no longer judge rbuf when the write fails

syzbot reported a uninit-value in cxusb_i2c_xfer. [1]

Only when the write operation of usb_bulk_msg() in dvb_usb_generic_rw()

succeeds and rlen is greater than 0, the read operation of usb_bulk_msg()

will be executed to read rlen bytes of data from the dvb device into the

rbuf.

In this case, although rlen is 1, the write operation failed which resulted

in the dvb read operation not being executed, and ultimately variable i was

not initialized.

[1]

BUG: KMSAN: uninit-value in cxusb_gpio_tuner drivers/media/usb/dvb-usb/cxusb.c:124 [inline]

BUG: KMSAN: uninit-value in cxusb_i2c_xfer+0x153a/0x1a60 drivers/media/usb/dvb-usb/cxusb.c:196

cxusb_gpio_tuner drivers/media/usb/dvb-usb/cxusb.c:124 [inline]

cxusb_i2c_xfer+0x153a/0x1a60 drivers/media/usb/dvb-usb/cxusb.c:196

__i2c_transfer+0xe25/0x3150 drivers/i2c/i2c-core-base.c:-1

i2c_transfer+0x317/0x4a0 drivers/i2c/i

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References