CVE-2024-35999

What it actually does

Missing channel lock when accessing ses channel index allows concurrent modification in SMB3 session handling, creating a data race condition.

Why it matters to the business

Potential for kernel instability or crashes during network file sharing on Linux systems may disrupt services and require unplanned downtime for updates.

How an attack unfolds

An attacker triggers concurrent SMB3 channel selection operations without the required lock to induce the data race; no widespread exploitation reported despite low EPSS and absence from KEV.

How to fix it

Update the Linux kernel to include commit 98c7ed29cd754ae7475dc7cb3f33399fda902729 or later equivalent stable releases across all affected distributions.

How to confirm the fix worked

Confirm the locking code around channel index access is present in the running kernel source or binary; test SMB3 multi-channel scenarios under load for race-free behavior.

Typical attack path

1. Gain ability to initiate multiple SMB3 sessions or channel operations on target
2. Force concurrent access to session channel index
3. Exploit missing lock to trigger race leading to inconsistent state or crash

How to detect it

Inspect kernel logs and SMB3 session traces for channel index access anomalies or race-related warnings; no specific post-exploitation artifacts known given lack of KEV activity.

What your security team should do

• Prioritize kernel upgrades to the fixed commit in all production Linux environments
• Review SMB3 usage and apply compensating controls such as disabling multi-channel if patching is delayed
• Monitor kernel update pipelines for regression testing on file serving workloads