CVE-2024-24864

What it actually does

Race condition in dvbdmx_write() within the Linux kernel media/dvb-core driver allows concurrent access leading to a null pointer dereference, resulting in kernel panic or denial of service.

Why it matters to the business

Systems relying on DVB media handling may experience sudden crashes or service interruptions, affecting media processing workloads and requiring reboots or restarts on affected Linux kernels.

How an attack unfolds

A local attacker with low-privileged access triggers concurrent writes to the DVB demux device while the driver is in a specific state, winning the race to dereference a null pointer and crash the kernel.

How to fix it

Update to a Linux kernel version that contains the fix for the race condition in dvbdmx_write(); if no fixed version is available, disable DVB media functionality or restrict access to /dev/dvb/* devices.

How to confirm the fix worked

Verify kernel source or changelog for the applied patch eliminating the race in dvbdmx_write(); test by attempting concurrent writes under load and confirm no null dereference occurs.

Typical attack path

1. Obtain local user access on a Linux system with DVB media support enabled
2. Open the DVB demux device and issue concurrent write operations
3. Time the writes to exploit the race condition in dvbdmx_write()
4. Trigger null pointer dereference causing kernel panic

How to detect it

Review kernel logs for null pointer dereference oops messages referencing dvbdmx_write or dvb-core around the time of unexpected reboots or panics; correlate with user activity on DVB devices.

What your security team should do

• Monitor for upstream kernel patches addressing the dvbdmx_write race condition
• Restrict local access to DVB devices via permissions or SELinux policies until patched
• Review systems using media/dvb-core and prioritize patching for high-availability media servers