Description

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

media: xc2028: avoid use-after-free in load_firmware_cb()

syzkaller reported use-after-free in load_firmware_cb() [1].
The reason is because the module allocated a struct tuner in tuner_probe(),
and then the module initialization failed, the struct tuner was released.
A worker which created during module initialization accesses this struct
tuner later, it caused use-after-free.

The process is as follows:

task-6504 worker_thread
tuner_probe <= alloc dvb_frontend [2]
...
request_firmware_nowait <= create a worker
...
tuner_remove <= free dvb_frontend
...
request_firmware_work_func <= the firmware is ready
load_firmware_cb <= but now the dvb_frontend has been freed

To fix the issue, check the dvd_frontend in load_firmware_cb(), if it is
null, report a warning and just return.

[1]:
==================================================================
BUG: KASAN: use-after-free in load_firmware_cb+0x1310/0x17a0
Read of size 8 at addr ffff8000d7ca2308 by task kworker/2:3/6504

Call trace:
load_firmware_cb+0x1310/0x17a0
request_firmware_work_func+0x128/0x220
process_one_work+0x770/0x1824
worker_thread+0x488/0xea0
kthread+0x300/0x430
ret_from_fork+0x10/0x20

Allocated by task 6504:
kzalloc
tuner_probe+0xb0/0x1430
...

Classification

CVE ID: CVE-2024-43900

CVSS Base Severity: HIGH

CVSS Base Score: 7.8

CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.04% (probability of being exploited)

EPSS Percentile: 10.26% (scored less or equal to compared to others)

EPSS Date: 2025-06-02 (when was this score calculated)

Stakeholder-Specific Vulnerability Categorization (SSVC)

SSVC Exploitation: none

SSVC Technical Impact: partial

SSVC Automatable: false

References

https://nvd.nist.gov/vuln/detail/CVE-2024-43900
https://git.kernel.org/stable/c/ef517bdfc01818419f7bd426969a0c86b14f3e0e
https://git.kernel.org/stable/c/850304152d367f104d21c77cfbcc05806504218b
https://git.kernel.org/stable/c/208deb6d8c3cb8c3acb1f41eb31cf68ea08726d5
https://git.kernel.org/stable/c/68594cec291ff9523b9feb3f43fd853dcddd1f60

Timeline