CVE-2024-46865

What it actually does

Uninitialized grc variable used after early return when fou pointer is NULL, resulting in memory corruption or undefined kernel behavior.

Why it matters to the business

Linux systems may experience crashes, data exposure, or denial of service; organizations running affected kernels face unplanned downtime and potential security exposure until updated.

How an attack unfolds

A local attacker with low privileges triggers the fou module initialization path that hits the NULL fou condition, causing the uninitialized grc to be dereferenced and leading to privilege escalation or system instability.

How to fix it

Update Linux kernel to version 5.10.227 or later; apply commit 392f6a97fcbecc64f0c00058b2db5bb0e4b8cc3e in stable trees; pterodactyl/wings users should upgrade to 1.2.1 or newer.

How to confirm the fix worked

Verify running kernel version is at or above the listed fixed releases; inspect kernel source for the corrected grc initialization order before the possible goto out path.

Typical attack path

1. Obtain local user access on affected Linux system
2. Trigger fou socket or tunnel creation that reaches the vulnerable initialization code path
3. Force the NULL fou branch to execute and consume the uninitialized grc value
4. Leverage resulting memory corruption for further exploitation or denial of service

How to detect it

Review kernel logs for oops or panic messages referencing fou and uninitialized variable usage; correlate with local process activity around fou module load times.

What your security team should do

• Prioritize kernel upgrades on all production Linux hosts within the next maintenance window
• Monitor EPSS and threat actor activity for any increase in Linux kernel local exploits
• Test patched kernels in staging before broad deployment
• Restrict untrusted local user access on systems that cannot be immediately updated