CVE-2026-93212 json
nfsd: guard nfsd_serv deref in nfsd_file_net_dispose
published last mo. modified 23d ago also EUVD-2026-85941
- cvss
- —
- not scored
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 6%
- public exploits
- 0
- none known
Summary
In the Linux kernel, the following vulnerability has been resolved:
nfsd: guard nfsd_serv deref in nfsd_file_net_dispose
nfsd_file_net_dispose() is the consumer side of l->freeme: the nfsd service thread loop calls it to drain entries that the filecache garbage collector and shrinker append via nfsd_file_dispose_list_delayed(). During per-net teardown, nn->nfsd_serv is cleared before the filecache laundrette is shut down, so the service thread can still run a dispose pass that finds more than eight entries on l->freeme and dereferences a NULL svc_serv:
nfsd service thread loop nfsd_file_net_dispose(nn) if (!list_empty(&l->freeme)) { ... svc_wake_up(nn->nfsd_serv); /* nn->nfsd_serv == NULL */ }
The sibling helper nfsd_file_dispose_list_delayed() already documents this ordering and caches nn->nfsd_serv into a local before testing it for NULL. nfsd_file_net_dispose() was introduced with the same raw svc_wake_up(nn->nfsd_serv) call and never picked up the guard.
Fix by loading nn->nfsd_serv into a local svc_serv pointer and only calling svc_wake_up() when it is non-NULL, matching the pattern in nfsd_file_dispose_list_delayed().
Patch / fix
- Linux Linux 6.12.109, 6.18.50, 7.2.4, 7.3
- linux Debian 13 6.12.111-1
- linux Debian 14 7.2.6-1
- linux-6.12 Debian 12 6.12.111-1~deb12u1
debian advisories DEBIAN-CVE-2026-93212
- linux Ubuntu 26.04 LTS 7.0.0-42.42
- linux-aws Ubuntu 26.04 LTS 7.0.0-1016.17
- linux-gcp Ubuntu 26.04 LTS 7.0.0-1016.18
- linux-ibm Ubuntu 26.04 LTS 7.0.0-1017.17
- linux-riscv Ubuntu 26.04 LTS 7.0.0-42.42.1
- linux-oracle Ubuntu 26.04 LTS 7.0.0-1015.16
- linux-hwe-7.0 Ubuntu 24.04 LTS 7.0.0-42.42~24.04.1
- linux-oem-7.0 Ubuntu 26.04 LTS 7.0.0-1017.17
ubuntu advisories UBUNTU-CVE-2026-93212
Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0
- kernel-64kb SLE Module for Basesystem 15 SP7 6.4.0-150700.53.84.1
- kernel-syms SLE Module for Development Tools 15 SP7 6.4.0-150700.53.84.1
- kernel-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.53.84.1
- kernel-source SLE Module for Development Tools 15 SP7, SLE Module for Basesystem 15 SP7 6.4.0-150700.53.84.1
- kernel-default SLE Workstation Extension 15 SP7, SLE Module for Legacy 15 SP7, SLE Module for Basesystem 15 SP7 +2 more 6.4.0-150700.53.84.1
- kernel-zfcpdump SLE Module for Basesystem 15 SP7 6.4.0-150700.53.84.1
- kernel-obs-build SLE Module for Development Tools 15 SP7 6.4.0-150700.53.84.1
- kernel-default-base SLE Module for Basesystem 15 SP7 6.4.0-150700.53.84.1.150700.17.47.1
suse advisories SUSE-SU-2026:4706-1SUSE-SU-2026:4640-1SUSE-SU-2026:24316-1SUSE-SU-2026:24315-1SUSE-SU-2026:24181-1SUSE-SU-2026:24182-1
- kernel-rt openSUSE Leap 16.0 6.12.0-160000.39.1
- dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.39.1
- kernel-64kb openSUSE Leap 16.0 6.12.0-160000.39.1
- kernel-syms openSUSE Leap 16.0 6.12.0-160000.39.1
- kernel-azure openSUSE Leap 16.0 6.12.0-160000.39.1
- kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.39.1
- kernel-source openSUSE Leap 16.0 6.12.0-160000.39.1
- kernel-default openSUSE Leap 16.0 6.12.0-160000.39.1
opensuse advisories openSUSE-SU-2026:22091-1openSUSE-SU-2026:11893-1
Is CVE-2026-93212 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
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What the vendors themselves say about their products: affected, fixed or not affected, and what to do.
red hat product security vex CVE-2026-93212 updated cvss 5.5
kernel: nfsd: guard nfsd_serv deref in nfsd_file_net_dispose
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Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +82 more Red Hat Enterprise Linux 10 kernel Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-9 Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9affected: no fix available “Fix deferred”
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Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-selftests-internal Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8not affected: vulnerable code not present
Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf
Exploit prediction
0.17% chance of exploitation in the next 30 days, higher than 6% of all scored CVEs (FIRST EPSS, 2026-11-11).
Affected products
- Linux Linux
Classification
- Technology feeds
References
Sources
- CVE List CVE-2026-93212
- NVD CVE-2026-93212
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