CVE-2026-90107

What the bug is

smc_llc_flow_stop() resets a flow struct with a blind memset: spin_lock_bh(&lgr->llc_flow_lock); memset(flow, 0, sizeof(*flow)); flow->type = SMC_LLC_FLOW_NONE; spin_unlock_bh(&lgr->llc_flow_lock); If flow->qentry is non-NULL at this point the pointer is overwritten without the allocation being freed, leaking one kmalloc object. A late-arriving duplicate CONFIRM_LINK or ADD_LINK_CONT message can set flow->qentry after the legitimate message has been consumed by the waiter via smc_llc_flow_qentry_clr() (which NULLs the pointer but leaves flow->type non-zero) but before the flow completes and smc_llc_flow_stop() runs. In that window the duplicate is stashed into flow->qentry, and then lost when smc_llc_flow_stop() zeros the struct. Call smc_llc_flow_qentry_del() inside the lock before the memset. smc_llc_flow_qentry_del() already checks flow->qentry before freeing, so the normal case where no entry is pending is a no-op.

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.

net/smc/smc_llc.c

What this is

SHARED MEMORY COMMUNICATIONS (SMC) SOCKETSMAINTAINERS section matched on net/smc/ · linux-rdma@vger.kernel.org · Supported

Kernel module

smc

Check it on the machine

grep -w CONFIG_SMC /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 smc

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 does not build this code in 2 releases. It does build it in 3 releases, so the answer depends on which release the machine runs.

• bookworm, trixiem
• forky, sidn
• bookworm · linux-6.12m

m

a loadable module on every flavour - check lsmod, can be blacklisted

n

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

Build switch

CONFIG_SMC

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

2026-09-17 (31 days ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.21%, higher than 10.6% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

not yet assignedsource

Subsystem

net/smc

Upstream fixes

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

Introduced	Fixed in	Commit
5.8	5.10.270	8e3deb150a52
5.8	5.15.221	11bc373ee663
5.8	6.1.188	032aec7d03c9
5.8	6.6.157	957dba2b8b5a
5.8	6.12.110	f03aa5d36ae3
5.8	6.18.52	0879ea157acc
5.8	7.2.6	5ff429dd6725
5.8	7.3	5ee0ceddc778

Debian advisories