CVE-2026-64103

What the bug is

The ISCI completion tasklet is initialized in isci_host_alloc() (drivers/scsi/isci/init.c:496) and scheduled from both MSI-X and legacy interrupt handlers (drivers/scsi/isci/host.c:223,613). isci_host_deinit() stops the controller and waits for stop completion, but it never kills completion_tasklet before teardown continues. A top-of-function tasklet_kill() is not sufficient here: interrupts are only disabled when isci_host_stop_complete() runs, so until wait_for_stop() returns the IRQ handlers can still requeue the tasklet. The tasklet callback also re-enables interrupts after draining completions, so killing the tasklet before the source is quiesced leaves the same race open. Once wait_for_stop() returns, no further IRQ-driven scheduling can occur. Kill completion_tasklet there so teardown cannot race a queued tasklet running on a dead ihost. On remove or unload, the stale callback can otherwise dereference ihost and touch ihost->smu_registers after the host lifetime ends. A UML + KASAN analogue reproduced the failure class both with no tasklet_kill() and with tasklet_kill() placed before source quiesce, and stayed clean once the kill happened after quiescing the scheduling source. This mirrors commit f6ab594672d4 ("scsi: aic94xx: fix use-after-free in device removal path"), but ISCI needs the kill after wait_for_stop().

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/scsi/isci/host.c

What this is

INTEL C600 SERIES SAS CONTROLLER DRIVERMAINTAINERS section matched on drivers/scsi/isci/ · linux-scsi@vger.kernel.org · Orphan

Kernel module

isci

Check it on the machine

grep -w CONFIG_SCSI_ISCI /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.

lsmod | grep -w isci

Prints a line if that module is loaded right now, and nothing if it is not. One that is not loaded can still be loaded later by anything that needs it.

Show whether Debian builds this, per release

Debian builds this, but not on every flavour. At least one release below builds the code on some of its kernel flavours and not on others, so the answer depends on the architecture and flavour installed.

• bookwormMnot built on amd64/cloud-amd64, arm64/arm64, arm64/cloud-arm64, arm64/rt/arm64, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, ppc64el/powerpc64le
• trixieMnot built on amd64/cloud-amd64, arm64/arm64, arm64/arm64-16k, arm64/cloud-arm64, arm64/rt/arm64, armel/rpi, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, riscv64/riscv64, s390x/s390x
• forky, sidMnot built on amd64/cloud-amd64, arm64/arm64, arm64/arm64-16k, arm64/cloud-arm64, arm64/rt-arm64, armhf/armmp, armhf/armmp-lpae, loong64/loong64, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, riscv64/riscv64, s390x/s390x

M

a module where it is built at all; some flavours do not build it

Build switch

CONFIG_SCSI_ISCI

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

2026-07-19 (3 months ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.13%, higher than 2.0% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

drivers/scsi

Upstream fixes

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

Introduced	Fixed in	Commit
3.0	5.10.258	1412995e10c7
3.0	5.15.209	a83d3e4daba4
3.0	6.1.175	ab2266601a87
3.0	6.6.142	309c6058622d
3.0	6.12.92	cb9e72c50e6c
3.0	6.18.34	b9ff86310062
3.0	7.0.11	6d40f2f103bb
3.0	7.1	b52a8d52c312