CVE-2026-97523 Linux CVE debrief

Who should care

Linux kernel maintainers, Linux system administrators, and security teams responsible for Linux systems. They should assess exposure and prioritize verification of affected systems. Linux kernel configurations and versions should be reviewed to determine potential exposure. System logs should be verified for signs of exploitation. Patches or updates provided by the Linux kernel maintainers should be applied.

Why it matters

A race condition vulnerability in the Linux kernel's mptcp scheduler has been resolved. Linux kernel maintainers and users should assess exposure and prioritize verification of affected systems.

• Verify Linux kernel configurations and versions to determine potential exposure
• Monitor system logs for signs of exploitation
• Prioritize patching or updating Linux kernel to prevent potential issues

Technical summary

The Linux kernel's mptcp scheduler has a race condition vulnerability that could lead to failed data transmission and a later release attempting to use a reset mss_now value of 0 for a divide operation. This vulnerability affects Linux kernel maintainers and users, who should assess exposure and prioritize verification of affected systems. The issue arises from a potential race between the scheduler and subflow sockets state change. Linux kernel maintainers and users should assess exposure and prioritize verification of affected systems.

Defensive priority

Linux kernel maintainers and users should assess exposure and prioritize verification of affected systems.

Recommended defensive actions

• Review Linux kernel configurations and versions to determine potential exposure
• Verify system logs for signs of exploitation
• Apply patches or updates provided by the Linux kernel maintainers
• Monitor system logs for signs of exploitation
• Prioritize patching or updating Linux kernel to prevent potential issues
• Verify Linux kernel configurations and versions to determine potential exposure
• Check relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

The CVE record and NVD entry provide limited information about the vulnerability. Further verification is required to determine the affected systems and potential impact. Linux kernel maintainers and users should assess exposure and prioritize verification of affected systems. The mptcp scheduler may race with subflow sockets state change: data transmission on the selected socket may fail and a later release could try to use mss_now reset to 0 for a divide operation.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.