CVE-2026-93189 Linux CVE debrief

Who should care

Linux kernel developers and maintainers, Linux distribution vendors, system administrators responsible for Linux kernel updates, security teams monitoring Linux kernel vulnerabilities

Why it matters

This use-after-free vulnerability in the Linux kernel's HID core requires attention from Linux kernel developers, maintainers, and system administrators. It can lead to potential system crashes or code execution when handling HID reports after a driver has freed the struct hidraw object. The fix centralizes quiesce in hid_hw_stop() to prevent use-after-free, and affected systems need to be patched or have compensating controls applied.

• Potential system crashes or code execution due to use-after-free when handling HID reports.
• Need to verify Linux kernel versions and HID driver usage to identify exposure.
• Prioritize patching or applying compensating controls for affected systems.
• Remediation requires updating Linux kernel versions with the centralized quiesce fix.

Technical summary

The Linux kernel's HID core has a use-after-free vulnerability due to a class-wide API misuse. Drivers that call hid_device_io_start() without a matching hid_device_io_stop() before hid_hw_stop() are exposed. The fix centralizes quiesce in hid_hw_stop() to prevent use-after-free. This change ensures that HID reports are properly quiesced before the struct hidraw object is freed, preventing potential crashes or code execution. Affected systems need to be patched or have compensating controls applied to mitigate the vulnerability.

Defensive priority

High

Recommended defensive actions

• Assess exposure for Linux kernel deployments using HID drivers, particularly those that call hid_device_io_start() without a matching hid_device_io_stop() before hid_hw_stop().
• Verify if Linux kernel versions in use have applied the centralized quiesce fix in hid_hw_stop().
• Inventory Linux kernel versions and HID driver usage to identify potentially affected systems.
• Prioritize patching or applying compensating controls for affected Linux kernel versions.
• 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 Linux kernel's HID core has a use-after-free vulnerability. A driver's probe enables input delivery via hid_device_io_start(), then fails and unwinds via hid_hw_stop(), which frees struct hidraw via hidraw_disconnect(). In-flight HID reports may still run on another CPU, causing a use-after-free through hidraw_report_event().

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.