CVE-2024-50058

What it actually does

Potential NULL pointer dereference in uart_shutdown() when calling uart_port_dtr_rts() without an uport validity check under HUPCL conditions, leading to kernel crash.

Why it matters to the business

Local denial of service causing system instability or reboot on affected Linux kernels; widespread kernel exposure increases operational risk for servers and devices using serial ports.

How an attack unfolds

An attacker with local access triggers UART port shutdown with HUPCL enabled; if uport is unexpectedly NULL the unprotected dereference crashes the kernel. No named threat actors have been observed exploiting this specific flaw.

How to fix it

Apply kernel patch 2fe399bb8efd0d325ab1138cf8e3ecf23a39e96d or later; update to fixed versions such as python-pillow 5.1.1-18.el8_5 where applicable and rebuild or reboot systems after patching.

How to confirm the fix worked

Verify presence of the commit in kernel source; test serial port open/close cycles with HUPCL enabled and confirm no NULL dereference occurs; monitor for Coverity-style static analysis findings on uart_port_dtr_rts calls.

Typical attack path

1. Obtain local user access on target Linux system
2. Configure or interact with serial device to set HUPCL flag
3. Trigger uart_shutdown() path during port close or hangup
4. Cause NULL uport dereference resulting in kernel panic

How to detect it

Inspect kernel logs for NULL pointer dereference oops during uart_shutdown or serial port close operations; correlate with processes accessing /dev/tty* devices; review audit logs for unusual serial port activity.

What your security team should do

• Prioritize kernel updates on systems exposing serial devices within 30 days
• Restrict local user access to serial ports via device permissions
• Enable kernel panic logging and watchdog for rapid detection of crashes
• Review downstream dependents of the Linux kernel for coordinated updates