# CVE-2026-80556: mmc: atmel-mci: Fix use-after-free in atmci_remove due to race condition

CVE-2026-80556 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-80556, released August 27, 2026. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2026-80556
- Priority: High
- CVSS: 7.8 (Moderate)
- EPSS: 0.0013
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Aug 26, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-80556

## Description

In the Linux kernel, the following vulnerability has been resolved:  mmc: atmel-mci: Fix use-after-free in atmci_remove due to race condition  In atmci_probe, &host->bh_work is bound with atmci_work_func, and atmci_interrupt, atmci_timeout_timer and atmci_dma_complete can all queue this work on system_bh_wq.  If we remove the module, atmci_remove makes cleanup and the memory allocated for host with devm_kzalloc() is released after the remove callback returns, while the work mentioned above may still be pending or running. The sequence of operations that may lead to a UAF bug is as follows:  CPU0                                      CPU1                                            | atmci_interrupt                                           | queue_work(system_bh_wq,                                           |            &host->bh_work) atmci_remove                              | atmci_cleanup_slot(...)                   | atmci_writel(host, ATMCI_IDR, ~0UL)       | timer_delete_sync(&host->timer)           | dma_release_channel(host->dma.chan)       | free_irq(platform_get_irq(pdev, 0), host) |                                           | atmci_work_func                                           | // use host // devm resources released after          | // remove returns, host is freed          |                                           | // use host (use-after-free)  Fix it by canceling the work after all the sources that can schedule it (IRQ handler, timeout timer and DMA completion callback) have been stopped, and before proceeding with the remaining cleanup in atmci_remove.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 13.5 (trixie) | 6.12.105-1 | [DEBIAN-CVE-2026-80556](https://patchblox.com/security/data/fix/linux/debian-cve-2026-80556.md) | Aug 27, 2026 |
| Linux | linux Debian 14 | 7.1.10-1 | [DEBIAN-CVE-2026-80556](https://patchblox.com/security/data/fix/linux/debian-cve-2026-80556.md) | Aug 27, 2026 |
| Linux | linux-6.12 Debian 12.15 (bookworm) | 6.12.107-1~deb12u1 | [DEBIAN-CVE-2026-80556](https://patchblox.com/security/data/fix/linux/debian-cve-2026-80556.md) | Aug 27, 2026 |

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Data as of 2026-11-08T19:12:23Z 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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