CVE-2022-4095

What it actually does

Use-after-free in cmd_hdl_filter in drivers/staging/rtl8712/rtl8712_cmd.c allows a local attacker to trigger memory corruption leading to denial of service or privilege escalation.

Why it matters to the business

Local attackers can crash affected systems or gain elevated privileges, disrupting operations and potentially compromising sensitive data on Linux-based infrastructure.

How an attack unfolds

An attacker with local user access crafts input that triggers the vulnerable command handler path in the rtl8712 staging driver, reusing freed memory to corrupt kernel structures and escalate privileges.

How to fix it

Upgrade the Linux kernel to a version containing commit c53b3dcb9942b8ed7f81ee3921c4085d87070c73 or later (equivalent to 5.19.2 or newer). Rebuild and reboot with the patched kernel; disable the rtl8712 staging driver if the hardware is not required.

How to confirm the fix worked

Verify the running kernel version is 5.19.2 or newer, or confirm the presence of commit c53b3dcb9942b8ed7f81ee3921c4085d87070c73 in the source tree. Test that the rtl8712 module loads without triggering the vulnerable code path.

Typical attack path

1. Obtain a local shell on an affected Linux system
2. Trigger the cmd_hdl_filter path via wireless device interaction
3. Exploit the use-after-free to corrupt kernel memory
4. Escalate privileges or cause denial of service

How to detect it

Review kernel logs for oops or panic messages referencing rtl8712_cmd.c or cmd_hdl_filter; look for unexpected privilege changes or process anomalies on systems running affected kernel versions.

What your security team should do

• Prioritize kernel updates on all systems using the rtl8712 driver
• Audit for presence of affected staging drivers and remove unnecessary ones
• Monitor vendor security advisories for backported fixes in supported distributions