CVE-2026-98130 Linux CVE debrief

Who should care

Linux kernel developers, administrators, and users of systems that utilize SCTP (Stream Control Transmission Protocol) should assess their exposure to this vulnerability. This includes but is not limited to Linux distribution maintainers, cloud providers, and organizations that rely on SCTP for network communications.

Why it matters

The CVE-2026-98130 vulnerability in the Linux kernel's SCTP_CMD_TIMER_START handler poses a significant risk due to a TOCTOU race condition. This condition can lead to use-after-free and potential code execution, making it critical for Linux kernel developers, administrators, and users to assess their exposure and apply necessary patches. The vulnerability's impact is heightened by its potential for denial of service and code execution, emphasizing the need for prompt verification and remediation.

• Potential denial of service due to use-after-free during association teardown.
• Possible code execution if an attacker can exploit the TOCTOU condition to manipulate the association reference count.
• Verification of kernel patch application to prevent exploitation.
• Assessment of SCTP usage and potential exposure in Linux kernel-based systems.

Technical summary

The SCTP_CMD_TIMER_START handler in the Linux kernel is vulnerable to a TOCTOU (Time-of-Check-to-Time-of-Use) race condition. This occurs when the timer_pending() check and timer_reduce() operations are performed, allowing the timer to expire and detach between these operations. As a result, timer_reduce() may rearm the timer without taking the required association reference, leading to an unbalanced association reference count. This can cause use-after-free during association teardown, potentially resulting in a denial of service or code execution.

Defensive priority

High

Recommended defensive actions

• Review and apply the provided kernel patches to address the TOCTOU race condition in the SCTP_CMD_TIMER_START handler.
• Ensure that the Linux kernel is updated to a version that includes the fix for this vulnerability.
• Monitor system logs for potential exploitation attempts or anomalies related to SCTP traffic.
• Perform an inventory of assets that use SCTP to determine potential exposure.
• Review compensating controls for exposed systems while remediation is scheduled and verified.
• Track exceptions, retest remediated assets, and close the item only after evidence is documented.
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.

Evidence notes

The issue was reported by Nico Yip (@_cyeaa_) working with TrendAI Zero Day Initiative. The CVE record and NVD entry provide details on the vulnerability. This TOCTOU race condition in the SCTP_CMD_TIMER_START handler of the Linux kernel can cause use-after-free and potential code execution. Linux kernel developers, administrators, and users should verify their exposure and apply necessary patches. Evidence is limited to public CVE details and NVD assessments.

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.