# CVE-2026-98903: mailbox: imx: Add a channel shutdown field

CVE-2026-98903 is fixed in linux on 1 platform, first by DEBIAN-CVE-2026-98903, released October 24, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-98903
- Priority: Routine
- CVSS: 4.7 (Moderate)
- EPSS: 0.0021
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 23, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-98903

## Description

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.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 13.5 (trixie) | 6.12.111-1 | [DEBIAN-CVE-2026-98903](https://patchblox.com/security/data/fix/linux/debian-cve-2026-98903.md) | Oct 24, 2026 |
| Linux | linux Debian 14 | 7.2.6-1 | [DEBIAN-CVE-2026-98903](https://patchblox.com/security/data/fix/linux/debian-cve-2026-98903.md) | Oct 24, 2026 |

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Data as of 2026-11-08T13:06:02Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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