CVE-2026-89732 Linux CVE debrief

Who should care

Linux kernel developers and maintainers, Linux distribution maintainers, and users of Linux-based systems who need to assess exposure and apply patches or updates to prevent potential deadlocks. These stakeholders should verify Linux kernel versions for exposure and apply patches or updates as necessary to prevent potential deadlocks.

Why it matters

A deadlock vulnerability exists in the Linux kernel's usb gadget driver, specifically in the f_fs (functionfs) component. This issue may impact Linux kernel developers, maintainers, and users of Linux-based systems who need to assess exposure and apply patches or updates to prevent potential deadlocks.

• Verify Linux kernel versions for exposure
• Apply patches or updates to affected Linux kernel versions
• Monitor Linux kernel updates for fixes

Technical summary

The Linux kernel's usb gadget driver, specifically the f_fs (functionfs) component, contains a deadlock vulnerability. The issue arises when the ffs_ep0_read() function holds the ffs->mutex while waiting for an event, potentially leading to a deadlock if the gadget is asynchronously torn down via configfs. This vulnerability can be triggered when a userspace daemon is polling ep0 via read() and the gadget is asynchronously torn down via configfs. Affected Linux kernel developers, maintainers, and users of Linux-based systems should assess exposure and apply patches or updates to prevent potential deadlocks.

Defensive priority

Medium

Recommended defensive actions

• Review Linux kernel versions and apply patches as necessary
• Monitor Linux kernel updates for fixes
• Assess exposure based on Linux kernel versions in use
• Verify Linux kernel versions for exposure
• 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.
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.

Evidence notes

The CVE Program record and NVD vulnerability detail provide official information about the vulnerability. The Linux kernel's official Git repository contains commits addressing the issue. Evidence limits and source grounding indicate that this vulnerability affects Linux kernel versions and requires patching or updates to prevent potential deadlocks. Defenders should verify Linux kernel versions for exposure and apply patches or updates as necessary.

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.