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Fencer Vulns
critical 9.8

CVE-2026-64534 in the critical feed json

nvmet-tcp: check INIT_FAILED before nvmet_req_uninit in digest error path

published 2026-07-27 3 mo ago modified 2026-11-03 5 d ago also EUVD-2026-49112

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 25%
public exploits
0
none known

Summary

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

nvmet-tcp: check INIT_FAILED before nvmet_req_uninit in digest error path

In nvmet_tcp_try_recv_ddgst(), when a data digest mismatch is detected, nvmet_req_uninit() is called unconditionally. However, if the command arrived via the nvmet_tcp_handle_req_failure() path, nvmet_req_init() had returned false and percpu_ref_tryget_live() was never executed. The unconditional percpu_ref_put() inside nvmet_req_uninit() then causes a refcount underflow, leading to a WARNING in percpu_ref_switch_to_atomic_rcu, a use-after-free diagnostic, and eventually a permanent workqueue deadlock.

Check cmd->flags & NVMET_TCP_F_INIT_FAILED before calling nvmet_req_uninit(), matching the existing pattern in nvmet_tcp_execute_request().

Patch / fix

  • Linux Linux 5.10.261, 5.12, 5.15.212, 6.1.178, 6.6.145, 6.12.97, 6.18.40, 7.1
  • linux Debian 12 6.1.180-1
  • linux Debian 13 6.12.100-1
  • linux Debian 14 7.1.3-1
  • linux-6.12 Debian 12 6.12.100-1~deb12u1

debian advisories DEBIAN-CVE-2026-64534

  • linux Ubuntu 22.04 LTS 5.15.0-198.208
  • linux Ubuntu 24.04 LTS 6.8.0-147.147
  • linux Ubuntu 26.04 LTS 7.0.0-34.34
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1117.124
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1067.70
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1013.13
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1118.128
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1071.79

ubuntu advisories UBUNTU-CVE-2026-64534

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 9 5.14.0-687.51.1.el9_8
  • rv RHEL 9 5.14.0-687.51.1.el9_8
  • perf RHEL 9 5.14.0-687.51.1.el9_8
  • rtla RHEL 9 5.14.0-687.51.1.el9_8
  • libperf RHEL 9 5.14.0-687.51.1.el9_8
  • kernel-rt RHEL 9 5.14.0-687.51.1.el9_8
  • kernel-64k RHEL 9 5.14.0-687.51.1.el9_8
  • kernel-core RHEL 9 5.14.0-687.51.1.el9_8

red hat advisories RHSA-2026:71232RHSA-2026:70498RHSA-2026:70403RHSA-2026:70402

  • kernel-source Linux Micro 6.0 6.4.0-159998.55.1
  • kernel-default Linux Micro 6.0 6.4.0-159998.55.1
  • kernel-kvmsmall Linux Micro 6.0 6.4.0-159998.55.1
  • kernel-default-base Linux Micro 6.0 6.4.0-159998.55.1.159998.21.42
  • kernel-64kb SLE Module for Basesystem 15 SP7 6.4.0-150700.53.90.1
  • kernel-syms SLE Module for Development Tools 15 SP7 6.4.0-150700.53.90.1
  • kernel-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.53.90.1
  • kernel-source SLE Module for Development Tools 15 SP7, SLE Module for Basesystem 15 SP7 6.4.0-150700.53.90.1

suse advisories SUSE-SU-2026:24550-1SUSE-SU-2026:5091-1SUSE-SU-2026:23887-1SUSE-SU-2026:23902-1SUSE-SU-2026:23897-1SUSE-SU-2026:23881-1

  • kernel-rt openSUSE Leap 16.0 6.12.0-160000.38.1
  • dtb-aarch64 openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-64kb openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-syms openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-azure openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-obs-qa openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-source openSUSE Leap 16.0 6.12.0-160000.38.1
  • kernel-default openSUSE Leap 16.0 6.12.0-160000.38.1

opensuse advisories openSUSE-SU-2026:21910-1

  • kernel AlmaLinux 9 5.14.0-687.51.1.el9_8
  • kernel-64k AlmaLinux 9 5.14.0-687.51.1.el9_8
  • kernel-core AlmaLinux 9 5.14.0-687.51.1.el9_8
  • kernel-64k-core AlmaLinux 9 5.14.0-687.51.1.el9_8
  • kernel-debug-core AlmaLinux 9 5.14.0-687.51.1.el9_8
  • kernel-64k-modules AlmaLinux 9 5.14.0-687.51.1.el9_8
  • kernel-debug-modules AlmaLinux 9 5.14.0-687.51.1.el9_8
  • kernel-64k-debug-core AlmaLinux 9 5.14.0-687.51.1.el9_8

almalinux advisories ALSA-2026:71232ALSA-2026:70498ALSA-2026:70402ALSA-2026:70403

  • kernel Rocky Linux 9 5.14.0-687.51.1.el9_8
  • kernel Rocky Linux 10 6.12.0-211.58.1.el10_2
  • kernel-rt Rocky Linux 8 4.18.0-553.166.1.rt7.507.el8_10
  • kernel Rocky Linux 8 4.18.0-553.166.1.el8_10

rocky linux advisories RLSA-2026:71232RLSA-2026:70498RLSA-2026:70403RLSA-2026:70402

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-2026-64534 updated cvss 7.5

kernel: nvmet-tcp: check INIT_FAILED before nvmet_req_uninit in digest error path

  • Red Hat Enterprise Linux 9 kernel-rt, kernel-rt-kvm, kernel-rt-core, kernel-rt-modules, kernel-rt-debug-kvm, kernel-rt-debug-core, +12 more
    affected: workaround, no fix available
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-687.51.1.el9_8, perf 5.14.0-687.51.1.el9_8, rtla 5.14.0-687.51.1.el9_8, python3-perf 5.14.0-687.51.1.el9_8, kernel-devel-matched 5.14.0-687.51.1.el9_8, kernel-64k-devel-matched 5.14.0-687.51.1.el9_8, +7 more
    fixed: vendor fix RHSA-2026:71232
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.58.1.el10_2, perf 6.12.0-211.58.1.el10_2, rtla 6.12.0-211.58.1.el10_2, python3-perf 6.12.0-211.58.1.el10_2, kernel-devel-matched 6.12.0-211.58.1.el10_2, kernel-64k-devel-matched 6.12.0-211.58.1.el10_2, +7 more
    fixed: vendor fix RHSA-2026:70498
  • Red Hat Enterprise Linux AppStream E4S (v.9.2) perf 5.14.0-284.202.1.el9_2, rtla 5.14.0-284.202.1.el9_2, kernel-devel-matched 5.14.0-284.202.1.el9_2, kernel-64k-devel-matched 5.14.0-284.202.1.el9_2, kernel-debug-devel-matched 5.14.0-284.202.1.el9_2, kernel-debuginfo-common-s390x 5.14.0-284.202.1.el9_2, +5 more
    fixed: vendor fix RHSA-2026:94477
  • Red Hat Enterprise Linux AppStream EUS (v. 10.0) rv 6.12.0-55.117.1.el10_0, perf 6.12.0-55.117.1.el10_0, rtla 6.12.0-55.117.1.el10_0, python3-perf 6.12.0-55.117.1.el10_0, kernel-devel-matched 6.12.0-55.117.1.el10_0, kernel-64k-devel-matched 6.12.0-55.117.1.el10_0, +7 more
    fixed: vendor fix RHSA-2026:94508
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.166.1.el8_10, kernel 4.18.0-553.166.1.el8_10, bpftool 4.18.0-553.166.1.el8_10, kernel-core 4.18.0-553.166.1.el8_10, kernel-tools 4.18.0-553.166.1.el8_10, python3-perf 4.18.0-553.166.1.el8_10, +15 more
    fixed: vendor fix RHSA-2026:70402
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-687.51.1.el9_8, kernel-64k 5.14.0-687.51.1.el9_8, kernel-core 5.14.0-687.51.1.el9_8, kernel-tools 5.14.0-687.51.1.el9_8, kernel-modules 5.14.0-687.51.1.el9_8, kernel-64k-core 5.14.0-687.51.1.el9_8, +27 more
    fixed: vendor fix RHSA-2026:71232
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.58.1.el10_2, kernel-64k 6.12.0-211.58.1.el10_2, kernel-core 6.12.0-211.58.1.el10_2, kernel-tools 6.12.0-211.58.1.el10_2, kernel-modules 6.12.0-211.58.1.el10_2, kernel-64k-core 6.12.0-211.58.1.el10_2, +28 more
    fixed: vendor fix RHSA-2026:70498
show 19 more
  • Red Hat Enterprise Linux BaseOS AUS (v.8.6) perf 4.18.0-372.227.1.el8_6, kernel 4.18.0-372.227.1.el8_6, bpftool 4.18.0-372.227.1.el8_6, kernel-core 4.18.0-372.227.1.el8_6, kernel-tools 4.18.0-372.227.1.el8_6, python3-perf 4.18.0-372.227.1.el8_6, +8 more
    fixed: vendor fix RHSA-2026:94996
  • Red Hat Enterprise Linux BaseOS E4S (v.9.2) bpftool 7.0.0-284.202.1.el9_2, kernel 5.14.0-284.202.1.el9_2, kernel-64k 5.14.0-284.202.1.el9_2, kernel-core 5.14.0-284.202.1.el9_2, kernel-tools 5.14.0-284.202.1.el9_2, python3-perf 5.14.0-284.202.1.el9_2, +28 more
    fixed: vendor fix RHSA-2026:94477
  • Red Hat Enterprise Linux BaseOS EUS (v. 10.0) kernel 6.12.0-55.117.1.el10_0, kernel-64k 6.12.0-55.117.1.el10_0, kernel-core 6.12.0-55.117.1.el10_0, kernel-tools 6.12.0-55.117.1.el10_0, kernel-modules 6.12.0-55.117.1.el10_0, kernel-64k-core 6.12.0-55.117.1.el10_0, +27 more
    fixed: vendor fix RHSA-2026:94508
  • Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.6) perf 4.18.0-372.227.1.el8_6, kernel 4.18.0-372.227.1.el8_6, bpftool 4.18.0-372.227.1.el8_6, kernel-core 4.18.0-372.227.1.el8_6, kernel-tools 4.18.0-372.227.1.el8_6, python3-perf 4.18.0-372.227.1.el8_6, +8 more
    fixed: vendor fix RHSA-2026:94996
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-687.51.1.el9_8, kernel-debuginfo-common-s390x 5.14.0-687.51.1.el9_8, kernel-debuginfo-common-x86_64 5.14.0-687.51.1.el9_8, kernel-debuginfo-common-aarch64 5.14.0-687.51.1.el9_8, kernel-debuginfo-common-ppc64le 5.14.0-687.51.1.el9_8
    fixed: vendor fix RHSA-2026:71232
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.58.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.58.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.58.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.58.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.58.1.el10_2
    fixed: vendor fix RHSA-2026:70498
  • Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0) libperf 6.12.0-55.117.1.el10_0, kernel-debuginfo-common-s390x 6.12.0-55.117.1.el10_0, kernel-debuginfo-common-x86_64 6.12.0-55.117.1.el10_0, kernel-debuginfo-common-aarch64 6.12.0-55.117.1.el10_0, kernel-debuginfo-common-ppc64le 6.12.0-55.117.1.el10_0
    fixed: vendor fix RHSA-2026:94508
  • Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.166.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.166.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.166.1.el8_10
    fixed: vendor fix RHSA-2026:70402
  • Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-kvm 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-core 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-modules 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-debug-kvm 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-debug-core 4.18.0-553.166.1.rt7.507.el8_10, +4 more
    fixed: vendor fix RHSA-2026:70403
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-687.51.1.el9_8, kernel-rt-64k 5.14.0-687.51.1.el9_8, kernel-rt-core 5.14.0-687.51.1.el9_8, kernel-rt-modules 5.14.0-687.51.1.el9_8, kernel-rt-64k-core 5.14.0-687.51.1.el9_8, kernel-rt-debug-core 5.14.0-687.51.1.el9_8, +14 more
    fixed: vendor fix RHSA-2026:71232
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.58.1.el10_2, kernel-rt-64k 6.12.0-211.58.1.el10_2, kernel-rt-core 6.12.0-211.58.1.el10_2, kernel-rt-modules 6.12.0-211.58.1.el10_2, kernel-rt-64k-core 6.12.0-211.58.1.el10_2, kernel-rt-debug-core 6.12.0-211.58.1.el10_2, +14 more
    fixed: vendor fix RHSA-2026:70498
  • Red Hat Enterprise Linux Real Time E4S (v.9.2) kernel-rt 5.14.0-284.202.1.rt14.487.el9_2, kernel-rt-core 5.14.0-284.202.1.rt14.487.el9_2, kernel-rt-modules 5.14.0-284.202.1.rt14.487.el9_2, kernel-rt-debug-core 5.14.0-284.202.1.rt14.487.el9_2, kernel-rt-modules-core 5.14.0-284.202.1.rt14.487.el9_2, kernel-rt-debug-modules 5.14.0-284.202.1.rt14.487.el9_2, +4 more
    fixed: vendor fix RHSA-2026:94558
  • Red Hat Enterprise Linux Real Time EUS (v. 10.0) kernel-rt 6.12.0-55.117.1.el10_0, kernel-rt-64k 6.12.0-55.117.1.el10_0, kernel-rt-core 6.12.0-55.117.1.el10_0, kernel-rt-modules 6.12.0-55.117.1.el10_0, kernel-rt-64k-core 6.12.0-55.117.1.el10_0, kernel-rt-debug-core 6.12.0-55.117.1.el10_0, +14 more
    fixed: vendor fix RHSA-2026:94508
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-687.51.1.el9_8, kernel-rt-core 5.14.0-687.51.1.el9_8, kernel-rt-modules 5.14.0-687.51.1.el9_8, kernel-rt-debug-core 5.14.0-687.51.1.el9_8, kernel-rt-modules-core 5.14.0-687.51.1.el9_8, kernel-rt-debug-modules 5.14.0-687.51.1.el9_8, +4 more
    fixed: vendor fix RHSA-2026:71232
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.58.1.el10_2, kernel-rt-core 6.12.0-211.58.1.el10_2, kernel-rt-modules 6.12.0-211.58.1.el10_2, kernel-rt-debug-core 6.12.0-211.58.1.el10_2, kernel-rt-modules-core 6.12.0-211.58.1.el10_2, kernel-rt-debug-modules 6.12.0-211.58.1.el10_2, +4 more
    fixed: vendor fix RHSA-2026:70498
  • Red Hat Enterprise Linux Real Time for NFV E4S (v.9.2) kernel-rt 5.14.0-284.202.1.rt14.487.el9_2, kernel-rt-kvm 5.14.0-284.202.1.rt14.487.el9_2, kernel-rt-core 5.14.0-284.202.1.rt14.487.el9_2, kernel-rt-modules 5.14.0-284.202.1.rt14.487.el9_2, kernel-rt-debug-kvm 5.14.0-284.202.1.rt14.487.el9_2, kernel-rt-debug-core 5.14.0-284.202.1.rt14.487.el9_2, +6 more
    fixed: vendor fix RHSA-2026:94558
  • Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0) kernel-rt 6.12.0-55.117.1.el10_0, kernel-rt-kvm 6.12.0-55.117.1.el10_0, kernel-rt-core 6.12.0-55.117.1.el10_0, kernel-rt-modules 6.12.0-55.117.1.el10_0, kernel-rt-debug-kvm 6.12.0-55.117.1.el10_0, kernel-rt-debug-core 6.12.0-55.117.1.el10_0, +6 more
    fixed: vendor fix RHSA-2026:94508
  • Red Hat Enterprise Linux RT (v. 8) kernel-rt 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-core 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-modules 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-debug-core 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-debug-modules 4.18.0-553.166.1.rt7.507.el8_10, kernel-rt-modules-extra 4.18.0-553.166.1.rt7.507.el8_10, +2 more
    fixed: vendor fix RHSA-2026:70403
  • 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

0.32% chance of exploitation in the next 30 days, higher than 25% 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

Weakness
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.