Skip to content
Fencer Vulns
critical 9.8

CVE-2026-89676 in the critical feed json

nfsd: fix stale s2s_cp_stateids IDR entry for async COPY

published 2026-09-11 58 d ago modified 2026-10-30 9 d ago also EUVD-2026-76588

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 42%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

nfsd: fix stale s2s_cp_stateids IDR entry for async COPY

For an async COPY, nfsd4_copy() called nfs4_init_copy_state() before dup_copy_fields(), so the s2s_cp_stateids IDR was pointed at &u->copy->cp_stateid -- memory in the per-rqstp COMPOUND buffer that is reused by the next request. dup_copy_fields() copies only the value into async_copy, so the IDR slot dangled at the transient buffer for the whole background copy. Any IDR walker then dereferences reused request memory: the laundromat reads cs_type from it and, if the bytes look like an expired NFS4_COPYNOTIFY_STID, follows into refcount_dec()/idr_remove()/kfree() on garbage; manage_cpntf_state() has the same exposure via idr_find().

Duplicate the fields first, then register the stateid on the stable async_copy. result->cb_stateid is unchanged.

Patch / fix

  • Linux Linux 6.1.191, 6.6.160, 6.12.111, 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-2026-89676

  • 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-2026-89676

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 RHEL 10.2 6.12.0-211.64.1.el10_2
  • rv RHEL 10.2 6.12.0-211.64.1.el10_2
  • perf RHEL 10.2 6.12.0-211.64.1.el10_2
  • rtla RHEL 10.2 6.12.0-211.64.1.el10_2
  • libperf RHEL 10.2 6.12.0-211.64.1.el10_2
  • kernel-rt RHEL 10.2 6.12.0-211.64.1.el10_2
  • kernel-64k RHEL 10.2 6.12.0-211.64.1.el10_2
  • kernel-core RHEL 10.2 6.12.0-211.64.1.el10_2

red hat advisories RHSA-2026:77690

  • kernel-source openSUSE Tumbleweed 7.2.6-1.1

opensuse advisories openSUSE-SU-2026:11805-1

  • kernel AlmaLinux 10 6.12.0-211.64.1.el10_2
  • rv AlmaLinux 10 6.12.0-211.64.1.el10_2
  • perf AlmaLinux 10 6.12.0-211.64.1.el10_2
  • rtla AlmaLinux 10 6.12.0-211.64.1.el10_2
  • libperf AlmaLinux 10 6.12.0-211.64.1.el10_2
  • kernel-rt AlmaLinux 10 6.12.0-211.64.1.el10_2
  • kernel-64k AlmaLinux 10 6.12.0-211.64.1.el10_2
  • kernel-core AlmaLinux 10 6.12.0-211.64.1.el10_2

almalinux advisories ALSA-2026:77690

  • kernel Rocky Linux 10 6.12.0-211.64.1.el10_2

rocky linux advisories RLSA-2026:77690

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-89676 updated cvss 8.8

kernel: nfsd: fix stale s2s_cp_stateids IDR entry for async COPY

  • Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8, openshift/ose-rhel-coreos-9
    affected: workaround, no fix available
  • Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    affected: workaround, no fix available “Fix deferred”
  • Red Hat Enterprise Linux kernel-modules-internal 6.12.0-211.64.1.el10_2 Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.64.1.el10_2, perf 6.12.0-211.64.1.el10_2, rtla 6.12.0-211.64.1.el10_2, python3-perf 6.12.0-211.64.1.el10_2, kernel-devel-matched 6.12.0-211.64.1.el10_2, kernel-64k-devel-matched 6.12.0-211.64.1.el10_2, +7 more Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.64.1.el10_2, kernel-64k 6.12.0-211.64.1.el10_2, kernel-core 6.12.0-211.64.1.el10_2, kernel-tools 6.12.0-211.64.1.el10_2, kernel-modules 6.12.0-211.64.1.el10_2, kernel-64k-core 6.12.0-211.64.1.el10_2, +28 more Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.64.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.64.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.64.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.64.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.64.1.el10_2 Red Hat Enterprise Linux Hidden (v. 10) kernel-modules-internal 6.12.0-211.64.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.64.1.el10_2 Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.64.1.el10_2, kernel-rt-64k 6.12.0-211.64.1.el10_2, kernel-rt-core 6.12.0-211.64.1.el10_2, kernel-rt-modules 6.12.0-211.64.1.el10_2, kernel-rt-64k-core 6.12.0-211.64.1.el10_2, kernel-rt-debug-core 6.12.0-211.64.1.el10_2, +14 more
    +1 more products
    Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.64.1.el10_2, kernel-rt-core 6.12.0-211.64.1.el10_2, kernel-rt-modules 6.12.0-211.64.1.el10_2, kernel-rt-debug-core 6.12.0-211.64.1.el10_2, kernel-rt-modules-core 6.12.0-211.64.1.el10_2, kernel-rt-debug-modules 6.12.0-211.64.1.el10_2, +4 more
    fixed: vendor fix RHSA-2026:77690
  • 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
    not 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

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
total
Assessed
23 d ago

Exploit prediction

0.49% chance of exploitation in the next 30 days, higher than 42% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.