CVE-2026-98968 Linux CVE debrief

Who should care

Linux kernel developers and maintainers, Linux distribution maintainers, System administrators and users of Linux-based systems, security teams, and operators of affected platforms should assess exposure and prioritize patching or mitigation efforts. This includes reviewing compensating controls, monitoring system logs, and verifying potential exploitation attempts.

Why it matters

This vulnerability could allow an attacker to potentially execute arbitrary code or cause a denial of service on affected Linux systems. Linux kernel developers and maintainers, Linux distribution maintainers, system administrators, and users of Linux-based systems should assess exposure and prioritize patching.

• Potential remote code execution
• Denial of Service (DoS) via crash or instability
• Elevation of privileges through exploitation

Technical summary

The vulnerability exists in the amt (Automatic Multicast Tunneling) module of the Linux kernel. A use-after-free error occurs in amt_dev_xmit() when an skb queued in a qdisc outlives the tunnel it references. This happens because the tunnel is referenced through a raw pointer in skb->cb, which can lead to potential remote code execution or denial of service on affected Linux systems. Linux kernel developers and maintainers should assess exposure and prioritize patching. System administrators and users of Linux-based systems should also review and apply patches or updates.

Defensive priority

High

Recommended defensive actions

• Review and apply the provided patches to the Linux kernel
• Update Linux kernel to a version that includes the fix
• Monitor system logs for potential exploitation attempts
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The vulnerability was introduced due to a raw pointer in skb->cb referencing the tunnel. The tunnel can be freed before the skb is dequeued, leading to a use-after-free error in amt_dev_xmit(). Limited source detail suggests explicit evidence of affected product deployments and defensive verification tasks are needed. Defenders should verify potential remote code execution or denial of service via crash or instability.

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.