CVE-2026-98441 Linux CVE debrief

Who should care

Defenders responsible for Linux kernel configurations and updates should assess exposure and prioritize verification of Linux kernel configurations and updates to prevent potential UAF errors. They should also review compensating controls for exposed systems while remediation is scheduled and verified.

Why it matters

Defenders should assess exposure and prioritize verification of Linux kernel configurations and updates to prevent potential UAF errors.

• Verify Linux kernel configurations to prevent potential UAF errors
• Assess connection tracking entry handling to prevent UAF errors
• Monitor for potential UAF errors in Linux kernel

Technical summary

The Linux kernel's net/sched: act_ct vulnerability arises when a packet with an unconfirmed connection tracking entry is cloned, and both clones are processed with different sets of extensions, potentially leading to a use-after-free (UAF) error. The fix resets the entry in case of shared unconfirmed ct entries. This vulnerability can be triggered when a packet is cloned and both clones are processed with different sets of extensions, which can lead to a UAF error when the connection tracking entry is destroyed. Defenders should assess exposure and prioritize verification of Linux kernel configurations and updates.

Defensive priority

Defenders should assess exposure and prioritize verification of Linux kernel configurations and updates.

Recommended defensive actions

• Assess Linux kernel configurations and updates
• Verify connection tracking entry handling
• Monitor for potential UAF errors
• 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 CVE record and NVD entry provide details on the vulnerability, but evidence is limited. The fixes tag points to the introduction of helpers, which is the main UAF trigger for sharing. Further verification is needed to confirm affected scope and severity. Defenders should review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance.

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.