CVE-2026-90358 Linux CVE debrief

Who should care

Linux kernel maintainers, Linux system administrators, and security teams responsible for Linux systems should assess exposure and prioritize verification of affected systems. Linux kernel users and operators should review Linux kernel configurations and versions to determine exposure and verify system registry and loaded modules for potential indicators of compromise.

Why it matters

A vulnerability in the Linux kernel's bpf subsystem has been resolved. Linux kernel maintainers and users should assess exposure and prioritize verification of affected systems.

• Verify Linux kernel configurations and versions to determine exposure
• Monitor system logs for suspicious activity
• Update to the latest Linux kernel version if possible

Technical summary

The Linux kernel's bpf subsystem has a vulnerability caused by an under-allocated register save area for 128-bit arguments. This can lead to adjacent stack slots being overwritten. The `btf_distill_func_proto` function accepts a function argument up to 16 bytes, but the current implementation assumes an __int128 argument only needs one register. Linux kernel maintainers and users should assess exposure and prioritize verification of affected systems. The vulnerability affects Linux kernel versions and maintainers should review compensating controls for exposed systems while remediation is scheduled and verified.

Defensive priority

Linux kernel maintainers and users should assess exposure and prioritize verification of affected systems.

Recommended defensive actions

• Review Linux kernel configurations and versions to determine exposure
• Verify system registry and loaded modules for potential indicators of compromise
• Update to the latest Linux kernel version if possible
• Monitor system logs for suspicious activity
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed.
• Check relevant monitoring, detection, and logs for exposed assets that need extra review.

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, but the scope of affected systems and versions is not explicitly stated. Linux kernel maintainers and users should verify Linux kernel configurations and versions to determine exposure. The vulnerability has been resolved in the Linux kernel, but the exact versions affected are not specified. 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.