---
id: "CVE-2026-99050"
kind: "vulnerability"
aliases: ["CVE-2026-99050"]
title: "Linux kernel GPIO MPSSE driver: race lets a USB unplug cause use-after-free"
severity: "unknown"
cvss: null
epss: 0.00206
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["gpio-mpsse", "linux-kernel", "package", "usb"]
not_affected_if: ["no-mpsse-usb-adapter"]
published_at: "2026-10-23T13:17:28+00:00"
first_seen_at: "2026-10-23T21:57:33+00:00"
updated_at: "2026-10-25T12:38:50+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-99050", "first_seen_at": "2026-10-23T21:57:33+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-99050", "first_seen_at": "2026-10-25T12:38:50+00:00"}]
---

# Linux kernel GPIO MPSSE driver: race lets a USB unplug cause use-after-free

In the Linux kernel's GPIO MPSSE driver, the IRQ poll worker can be armed after the disconnect teardown has already scanned for workers, so the worker keeps running on freed memory. The sources describe a use-after-free in the kernel's USB-attached MPSSE GPIO path; they do not state what an attacker can do with it.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- unknown

## Fix

- Update the Linux kernel to a release that includes the upstream commit fixing gpio: mpsse IRQ poll worker arming (the sources do not name the version).

## Timeline

- 2026-10-23T21:57:33+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-99050
- 2026-10-25T12:38:50+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-99050

## From the sources

In the Linux kernel, the following vulnerability has been resolved:

gpio: mpsse: fix race when arming the IRQ poll worker

gpio_mpsse_irq_enable() arms the poll worker before publishing it:
schedule_work() runs before the worker is added to priv->workers. If
gpio_mpsse_disconnect() walks the list in that window it misses the
worker, and once disconnect returns, the USB core frees mpsse_priv
while the orphaned gpio_mpsse_poll() work keeps accessing it, causing
a use-after-free.

Fix this by publishing and arming the worker in one irq_spin
critical section. Teardown walks the same list under irq_spin, so a
worker found on the list is guaranteed to be armed, and
cancel_work_sync() handles it whether it is queued or running.

A worker armed after the disconnect walk would still be missed, so
also set a new priv->dying flag under irq_spin before the teardown
walk, and check it in the same critical section, freeing it via
kfree_rcu() instead when the device is going away, since kfree()
would be called with the IRQ core's raw spinlock held and may sleep
on PREEMPT_RT. schedule_work() is safe to call with irq_spin held,
and the next probe gets a fresh mpsse_priv, so the flag never needs
to be cleared.

This issue was found by an in-house static analysis tool.

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