CVE-2024-49573

What it actually does

A race condition in the Linux kernel scheduler fair class allows the next buddy entity to become delayed under NEXT_BUDDY, triggering a warning inside pick_next_entity().

Why it matters to the business

Kernel warnings or scheduler instability on Linux systems with NEXT_BUDDY enabled, risking degraded performance or crashes in multi-task workloads; no ransomware use or active threat actors reported and low exploit likelihood reduces urgency.

How an attack unfolds

An attacker with local access enables NEXT_BUDDY and creates scheduling conditions that turn the next buddy delayed, causing the warning during entity selection; no remote vectors or named threat actors are known.

How to fix it

Upgrade the Linux kernel to version 6.12.7 or later, or apply commit 5dbe6816c49197677a5ecce749bd99929da147da from the stable git tree.

How to confirm the fix worked

Confirm running kernel is 6.12.7 or newer and verify the clear_buddies() relocation is present in sched/fair.c source.

Typical attack path

1. Gain local shell or process execution
2. Enable the NEXT_BUDDY scheduler feature
3. Trigger delayed dequeue of a runnable task marked as next buddy
4. Force pick_next_entity() to hit the warning path

How to detect it

Search kernel logs and dmesg for warnings referencing pick_next_entity or NEXT_BUDDY after the feature is enabled.

What your security team should do

• Apply the 6.12.7 kernel update across all Linux hosts
• Review scheduler configuration and disable NEXT_BUDDY where not required
• Monitor kernel logs for pick_next_entity warnings until patching completes