CVE-2026-93211

What the bug is

shrinker_register() precedes the INIT_LIST_HEAD loop and the drc_hashsize store. On weakly-ordered architectures (arm64, ppc), a shrinker scan can observe drc_hashsize before the bucket list heads are initialized, causing a NULL deref in the DRC shrinker callback. Move bucket initialization and the drc_hashsize store before shrinker_register() so the hash table is fully initialized before it becomes visible to the shrinker.

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.

fs/nfsd/nfscache.c

What this is

KERNEL NFSD, SUNRPC, AND LOCKD SERVERSMAINTAINERS section matched on fs/nfsd/ · linux-nfs@vger.kernel.org · Supported

Kernel module

nfsd

Check it on the machine

grep -w CONFIG_NFSD /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 nfsd

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 as a loadable module. Every release below compiles it as a module on every flavour, so whether the code is in the running kernel depends on whether that module is loaded.

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

m

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

Build switch

CONFIG_NFSD

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

2026-09-24 (24 days ago)source

CVSS

no vector published, unrated

Attack vector

not published

EPSS

0.17%, higher than 5.6% of all CVEssource

CISA KEV

not listedthe KEV catalogue

Debian urgency

unimportantsource

Subsystem

fs/nfsd

Upstream fixes

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

Introduced	Fixed in	Commit
6.7	6.12.109	f060f43a6763
6.7	6.18.50	b57bd8cb739c
6.7	7.2.4	431c70ca5163
6.7	7.3	b0c58934f5cc

Debian advisories