CVE-2016-7913

What it actually does

Use-after-free in xc2028_set_config allows local users to corrupt kernel memory when the firmware name is omitted from the tuner configuration data structure.

Why it matters to the business

Attackers with local access on affected Linux systems can crash the kernel or escalate privileges, leading to system downtime or full host compromise on systems using the xc2028 tuner.

How an attack unfolds

A local attacker invokes the xc2028_set_config function without supplying a firmware name, leaving a dangling pointer in the tuner data structure that is later dereferenced, resulting in arbitrary kernel memory corruption that can be leveraged for privilege escalation or denial of service.

How to fix it

Upgrade the Linux kernel to a version containing commit 8dfbcc4351a0b6d2f2d77f367552f48ffefafe18 or later; rebuild and reboot with the patched kernel image.

How to confirm the fix worked

Verify the running kernel source contains commit 8dfbcc4351a0b6d2f2d77f367552f48ffefafe18 or inspect the xc2028_set_config function to confirm the firmware name check is present before any pointer use.

Typical attack path

1. Obtain local shell access on a vulnerable Linux host with the xc2028 tuner driver loaded
2. Craft and submit a configuration request that omits the firmware name field
3. Trigger repeated calls to xc2028_set_config to induce the use-after-free condition
4. Exploit the resulting kernel memory corruption to execute arbitrary code or cause a crash

How to detect it

Review kernel logs for oops or panic entries referencing tuner-xc2028.c or xc2028_set_config; examine audit logs for unusual local process activity targeting media tuners.

What your security team should do

• Apply the kernel patch containing commit 8dfbcc4351a0b6d2f2d77f367552f48ffefafe18 immediately on all affected systems
• Restrict local user accounts and remove unnecessary media/tuner driver modules where possible
• Monitor for kernel oops or panic logs related to tuner-xc2028.c until patching is complete