CVE-2023-31082

What it actually does

A sleeping function is invoked from an invalid context within the gsmld_write function in the n_gsm driver, potentially causing the kernel to block.

Why it matters to the business

On affected Linux systems this could lead to system instability or hangs though the issue is disputed and may not represent a true vulnerability; low prevalence and no known exploits reduce operational risk.

How an attack unfolds

An attacker with local access would need to interact with the GSM multiplexing driver to trigger the invalid context call but exploitation is unlikely given the disputed status and lack of public exploits.

How to fix it

No fixed versions available; monitor kernel updates and consider disabling the GSM driver if unused.

How to confirm the fix worked

Review kernel source for gsmld_write and check for context handling; test on non-production systems with GSM enabled.

Typical attack path

1. Obtain local access to a Linux system
2. Trigger the n_gsm driver through specific TTY operations
3. Cause the sleeping function to be called improperly

How to detect it

Monitor for kernel logs indicating blocked tasks or sleeping in invalid contexts related to n_gsm; review system calls involving TTY GSM.

What your security team should do

• Assess if the GSM driver is in use in the environment
• Apply latest kernel patches as they become available
• Disable unnecessary TTY drivers