CVE-2024-47668

What it actually does

Race condition in __genradix_ptr_alloc allows a preallocated radix tree node to retain a stale pointer to the old root instead of being zeroed when depth increase races occur.

Why it matters to the business

Kernel memory corruption or crashes can occur under concurrent workloads, leading to system instability, potential data loss, and operational downtime in Linux-based servers and containers; low exploit likelihood but high impact on affected kernels and build tools.

How an attack unfolds

An attacker triggers concurrent allocations that increase tree depth; one thread's preallocated node loses the race, retains an old root pointer, and later gets used as a non-root node, causing use of uninitialized or invalid memory.

How to fix it

Upgrade Linux kernel to commit 0f27f4f445390cb7f73d4209cb2bf32834dc53da or later stable releases; upgrade github.com/moby/buildkit to version 0.12.5 or newer. Reboot systems after kernel updates.

How to confirm the fix worked

Verify kernel source contains the zeroing in the cmpxchg failure path of __genradix_ptr_alloc; confirm buildkit version >= 0.12.5 via package manager or container image inspection; run stress tests exercising concurrent radix allocations.

Typical attack path

1. Identify workload that performs concurrent radix tree allocations requiring depth growth
2. Race multiple threads to trigger __genradix_ptr_alloc depth increase simultaneously
3. Force reuse of the raced preallocated node as a non-root node
4. Trigger dereference or traversal of the stale pointer for memory corruption or crash

How to detect it

Review kernel logs for oops or panic entries involving generic radix tree functions; search audit and system call logs for unusual concurrent allocation patterns; no public exploitation artifacts known.

What your security team should do

• Prioritize kernel and buildkit updates on all Linux hosts and container build pipelines within standard maintenance windows
• Monitor EPSS and KEV status for any future increase in exploit activity
• Enable kernel memory debugging and fuzzing on test systems to validate the race is closed