CVE-2026-80556

What the bug is

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 lives

The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.

drivers/mmc/host/atmel-mci.c

What this is

MICROCHIP MMC/SD/SDIO MCI DRIVERMAINTAINERS section matched on drivers/mmc/host/atmel-mci.c · Maintained

Kernel module

none to look for. The file would have gone into atmel_mci, and Debian does not compile it into that module, so finding atmel_mci in lsmod would say nothing about this CVE.

Check it on the machine

grep -w CONFIG_MMC_ATMELMCI /boot/config-$(uname -r)

Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.

Show whether Debian builds this, per release

Debian does not build this code. In 5 releases below, every kernel flavour Debian publishes has the switch off, so the vulnerable file is compiled into no kernel binary Debian ships.

• bookworm, trixie, forky, sid, bookworm · linux-6.12n

n

not enabled on any flavour - this release does not build the code

Build switch

CONFIG_MMC_ATMELMCI

From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages

Signals

Published

2026-08-26 (2 months ago)source

CVSS

7.8 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsource recompute it

Attack vector

local (AV:L)source

EPSS

0.17%, higher than 6.0% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

drivers/mmc

Upstream fixes

The versions the CNA records as introducing and fixing this, and the commit for each. source

Introduced	Fixed in	Commit
2.6.27	6.12.105	22aecf6c4721
2.6.27	6.18.46	b5060ff2f546
2.6.27	7.1.10	7599a73ff66d
2.6.27	7.2	c125ee35a49a

Debian advisories