CVE-2021-47583: media: mxl111sf: change mutex_init() location

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-06-19 · updated 2026-06-17
Weakness: CWE-908

Description

In the Linux kernel, the following vulnerability has been resolved: media: mxl111sf: change mutex_init() location Syzbot reported, that mxl111sf_ctrl_msg() uses uninitialized mutex. The problem was in wrong mutex_init() location. Previous mutex_init(&state->msg_lock) call was in ->init() function, but dvb_usbv2_init() has this order of calls: dvb_usbv2_init() dvb_usbv2_adapter_init() dvb_usbv2_adapter_frontend_init() props->frontend_attach() props->init() Since mxl111sf_* devices call mxl111sf_ctrl_msg() in ->frontend_attach() internally we need to initialize state->msg_lock before frontend_attach(). To achieve it, ->probe() call added to all mxl111sf_* devices, which will simply initiaize mutex.

Affected products

Linux kernel: from 3.7 before 4.19.222; from 4.20 before 5.4.168; from 5.5 before 5.10.88; from 5.11 before 5.15.11 — fixed in 4.19.222, 5.10.88, 5.15.11, 5.4.168

How to fix

Upgrade to a fixed version: Linux kernel 4.19.222, 5.10.88, 5.15.11, 5.4.168. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2021-47583 or the next vulnerability affects your stack