CVE-2026-89486 Linux CVE debrief

Who should care

Defenders responsible for Linux kernel-based systems, particularly those using IPMI, should assess exposure and prioritize patching. This includes operators managing Linux kernel-based systems, vulnerability management teams, and security teams responsible for ensuring the security and integrity of IPMI configurations. Additionally, system administrators and IT professionals responsible for maintaining and securing Linux kernel-based systems should be made

Why it matters

A use-after-free vulnerability in the Linux kernel's IPMI subsystem requires verification and patching to prevent potential system instability, privilege escalation, or denial-of-service attacks.

• Potential system crashes or instability due to use-after-free errors
• Possible elevation of privileges or unauthorized access
• Increased risk of denial-of-service (DoS) attacks
• Need for verification of Linux kernel versions and IPMI configurations

Technical summary

The vulnerability occurs in the _ipmi_destroy_user() function, where a command receiver (cmd_rcvr) is freed without a proper synchronization, leading to a potential use-after-free error. This was caused by a commit that removed srcu for the ipmi_interfaces list but did not properly address the cmd_rcvrs list, which still relies on plain RCU. The missing synchronize_rcu() call between unlinking command receivers from the intf->cmd_rcvrs list and freeing them can lead to a use-after-free error. This vulnerability can result in potential system instability, privilege escalation, or denial-of-service attacks if exploited.

Defensive priority

Defenders should prioritize verifying and applying patches for Linux kernel versions affected by this vulnerability, particularly in systems where IPMI is used.

Recommended defensive actions

• Verify and apply patches for Linux kernel versions affected by this vulnerability
• Review system configurations and ensure IPMI is properly secured
• Monitor system logs for potential exploitation attempts
• Conduct a thorough review of IPMI configurations and ensure they align with organizational security policies
• Perform a vulnerability assessment to identify potential exposure in Linux kernel-based systems
• Develop and implement compensating controls for exposed systems while remediation is scheduled and verified
• Track and document remediation efforts, including testing and validation of patched systems

Evidence notes

The vulnerability was introduced due to a missing synchronize_rcu() call between unlinking command receivers from the intf->cmd_rcvrs list and freeing them. This was caused by a commit that removed srcu for the ipmi_interfaces list but did not properly address the cmd_rcvrs list, which still relies on plain RCU.

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.