CVE-2024-27404

What it actually does

The flaw is a data race on the remote_id field in the Linux kernel's MPTCP implementation, where concurrent access without proper memory ordering annotations can lead to inconsistent reads and potential system instability or denial of service.

Why it matters to the business

Organizations running affected Linux kernels may experience unexpected system crashes or degraded network performance in multi-path TCP scenarios, requiring urgent patching to maintain stability across servers and devices; the issue has low exploitation probability but affects a widely used kernel component with many downstream dependents.

How an attack unfolds

An attacker with local access and specific timing conditions can trigger concurrent operations on MPTCP sockets to exploit the unsynchronized remote_id access, potentially causing a crash; no named threat actors have been observed exploiting this, and it has not appeared in ransomware campaigns.

How to fix it

Upgrade to fixed kernel versions such as those containing commit e64148635509bf13eea851986f5a0b150e5bd066; for Debian rsync packages update to 2.6.9-5 or later equivalents that incorporate the kernel fix.

How to confirm the fix worked

Verify the running kernel includes the ONCE annotations for remote_id access via source inspection or by checking against the fixed commit hash; test MPTCP workloads for absence of data race warnings under concurrency.

Typical attack path

1. Obtain local user access on a system running an unpatched Linux kernel with MPTCP enabled
2. Craft or trigger concurrent MPTCP connection operations that race on remote_id reads/writes
3. Cause memory inconsistency leading to kernel panic or service disruption

How to detect it

Review kernel logs for MPTCP-related race warnings or panics around socket operations; no widespread exploitation indicators exist given the KEV false status and low EPSS.

What your security team should do

• Prioritize kernel upgrades on all systems using MPTCP within the next maintenance window given the 880 days since publication
• Monitor EPSS trends (stable at ~0.004) and apply patches to reduce availability risks
• Audit for MPTCP usage in network configurations and disable if not required