---
id: "CVE-2026-98903"
kind: "vulnerability"
aliases: ["CVE-2026-98903"]
title: "Linux kernel: i.MX mailbox shutdown race can leave interrupt enabled"
severity: "unknown"
cvss: null
epss: 0.00206
exploited: false
status: "open"
category: "other"
products: []
ecosystems: []
tags: ["i.mx", "linux", "mailbox", "other"]
not_affected_if: []
published_at: "2026-10-23T12:18:24+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-2026-98903", "first_seen_at": "2026-10-23T21:57:33+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-98903", "first_seen_at": "2026-10-25T12:38:50+00:00"}]
---

# Linux kernel: i.MX mailbox shutdown race can leave interrupt enabled

A race in the i.MX mailbox driver can leave a receive interrupt enabled after a channel is shut down, which can trigger spurious interrupts on shared handlers. The sources describe a teardown timing issue, not a confirmed code execution or data exposure path.

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

## Timeline

- 2026-10-23T21:57:33+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-98903
- 2026-10-25T12:38:50+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-98903

## From the sources

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

mailbox: imx: Add a channel shutdown field

sashiko complained about possible teardown problem. The scenario

 CPU 0                              CPU 1
  imx_mu_isr()                   imx_mu_shutdown()
                                   imx_mu_xcr_rmw(priv, IMX_MU_RCR, 0, IMX_MU_xCR_RIEn(priv->dcfg->type, cp->idx));
    imx_mu_specific_rx()
      imx_mu_xcr_rmw(priv, IMX_MU_RCR, IMX_MU_xCR_RIEn(priv->dcfg->type, 0), 0);
                                   free_irq()

The RX event remains enabled because in this short window the RX event
was disabled in ->shutdown() while the interrupt was active and then
enabled again by the ISR while ->shutdown waited in free_irq().

This race requires timing and if happens can be problematic on shared
handlers if the "removed" channel triggers an interrupt. In this case
the irq-core will shutdown the interrupt with the "nobody cared"
message.

Introduce imx_mu_con_priv::shutdown to signal that the channel is
shutting down. This flag is set with the lock held (by
imx_mu_xcr_clr_shut()). The unmask side uses imx_mu_xcr_set_act() which
only enables the event if the channel has not been shutdown and
serialises on the same lock.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_