CVE-2026-46116 Linux CVE debrief

Who should care

Linux kernel developers and maintainers, Linux distribution maintainers, and users of Linux-based systems should be aware of this vulnerability and take necessary actions to mitigate its impact. This includes assessing exposure, applying patches or mitigations, and monitoring system calls and network traffic for potential exploitation attempts. Additionally, Linux kernel developers and maintainers should review and update Linux kernel versions to ensure a

Why it matters

A use-after-free vulnerability in the Linux kernel's xfrm state management can lead to potential privilege escalation or denial-of-service. Linux kernel developers, maintainers, and users should assess exposure and apply patches or mitigations as needed.

• Potential privilege escalation
• Potential denial-of-service due to system crash
• Verification of Linux kernel versions and patch application
• Monitoring system calls and network traffic for potential exploitation attempts

Technical summary

The vulnerability occurs in the `__xfrm_state_delete` function, which can lead to a slab-use-after-free error. The issue was resolved by using `hlist_del_init_rcu` instead of `hlist_del_rcu` and testing `hlist_unhashed` rather than value predicates for `byseq` and `byspi`. This change ensures that the deletion of xfrm_state objects is handled safely, preventing use-after-free errors. Linux kernel developers and maintainers should assess the vulnerability and apply patches or mitigations as needed to prevent potential privilege escalation or denial-of-service attacks.

Defensive priority

High

Recommended defensive actions

• Apply patches provided by the Linux kernel maintainers
• Review and update Linux kernel versions to ensure the fix is applied
• Monitor system calls and network traffic for potential exploitation attempts
• Perform vulnerability scanning to identify potentially affected systems
• 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 in the Linux kernel and can be triggered through a specially crafted sequence of system calls. The issue was resolved by using `hlist_del_init_rcu` instead of `hlist_del_rcu` and testing `hlist_unhashed` rather than value predicates for `byseq` and `byspi`.

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.