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/i2c-core-base.c:2315
i2c_transfer_buffer_flags+0x125/0x1e0 drivers/i2c/i2c-core-base.c:2343
i2c_master_send include/linux/i2c.h:109 [inline]
i2cdev_write+0x210/0x280 drivers/i2c/i2c-dev.c:183
do_loop_readv_writev fs/read_write.c:848 [inline]
vfs_writev+0x963/0x14e0 fs/read_write.c:1057
do_writev+0x247/0x5c0 fs/read_write.c:1101
__do_sys_writev fs/read_write.c:1169 [inline]
__se_sys_writev fs/read_write.c:1166 [inline]
__x64_sys_writev+0x98/0xe0 fs/read_write.c:1166
x64_sys_call+0x222...

Classification

CVE ID: CVE-2025-38229

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.02% (probability of being exploited)

EPSS Percentile: 4.96% (scored less or equal to compared to others)

EPSS Date: 2025-07-06 (when was this score calculated)

References

https://nvd.nist.gov/vuln/detail/CVE-2025-38229
https://git.kernel.org/stable/c/390b864e3281802109dfe56e508396683e125653
https://git.kernel.org/stable/c/41807a5f67420464ac8ee7741504f6b5decb3b7c
https://git.kernel.org/stable/c/84eca597baa346f09b30accdaeca10ced3eeba2d
https://git.kernel.org/stable/c/04354c529c8246a38ae28f713fd6bfdc028113bc
https://git.kernel.org/stable/c/9bff888c92f5c25effbb876d22a793c2388c1ccc
https://git.kernel.org/stable/c/8b35b50b7e98d8e9a0a27257c8424448afae10de
https://git.kernel.org/stable/c/73fb3b92da84637e3817580fa205d48065924e15

Timeline