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Fencer Vulns
high 7.5

CVE-2026-89481 json

nvme-tcp: fix host memory disclosure on R2T for a read command

published 2026-09-11 58 d ago modified 2026-10-30 9 d ago also EUVD-2026-76387

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 37%
public exploits
0
none known

Summary

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

nvme-tcp: fix host memory disclosure on R2T for a read command

nvme_tcp_handle_r2t() does not check the direction of the request the R2T refers to. A malicious controller can send an R2T for a READ and the host will answer it: nvme_tcp_setup_h2c_data_pdu() builds the H2CData header and nvme_tcp_try_send_data() sends the request's data buffer. That buffer is the READ destination, so its contents go to the controller.

The command then completes normally and nothing is logged.

Against a test controller that answers every READ with an R2T, a 4096 byte buffered read returned all 4096 bytes, split over two R2Ts. The pages contained stale kernel data, including an array of struct page pointers.

Reject an R2T for a request that is not a write.

Patch / fix

  • Linux Linux 5.10.273, 5.15.224, 6.1.188, 6.6.157, 6.12.109, 6.18.50, 7.2.4, 7.3
  • linux Debian 12 6.1.190-1
  • 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-2026-89481

  • 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-2026-89481

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 5.14.0-687.55.1.el9_8
  • rv RHEL 9 5.14.0-687.55.1.el9_8
  • perf RHEL 9 5.14.0-687.55.1.el9_8
  • rtla RHEL 9 5.14.0-687.55.1.el9_8
  • libperf RHEL 9 5.14.0-687.55.1.el9_8
  • kernel-rt RHEL 9 5.14.0-687.55.1.el9_8
  • kernel-64k RHEL 9 5.14.0-687.55.1.el9_8
  • kernel-core RHEL 9 5.14.0-687.55.1.el9_8

red hat advisories RHSA-2026:76739RHSA-2026:75747RHSA-2026:75746RHSA-2026:71602

  • 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-2026:4687-1SUSE-SU-2026:4640-1SUSE-SU-2026:24316-1SUSE-SU-2026:24315-1SUSE-SU-2026:24181-1

  • 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-2026:11880-1

  • kernel-rt AlmaLinux 8 4.18.0-553.171.1.rt7.512.el8_10
  • kernel-rt-core AlmaLinux 8 4.18.0-553.171.1.rt7.512.el8_10
  • kernel-rt-modules AlmaLinux 8 4.18.0-553.171.1.rt7.512.el8_10
  • kernel-rt-debug-core AlmaLinux 8 4.18.0-553.171.1.rt7.512.el8_10
  • kernel-rt-debug-modules AlmaLinux 8 4.18.0-553.171.1.rt7.512.el8_10
  • kernel-rt-modules-extra AlmaLinux 8 4.18.0-553.171.1.rt7.512.el8_10
  • kernel-rt-debug-modules-extra AlmaLinux 8 4.18.0-553.171.1.rt7.512.el8_10
  • kernel AlmaLinux 8 4.18.0-553.171.1.el8_10

almalinux advisories ALSA-2026:75746ALSA-2026:75747ALSA-2026:71602

  • kernel-rt Rocky Linux 8 4.18.0-553.171.1.rt7.512.el8_10
  • kernel Rocky Linux 8 4.18.0-553.171.1.el8_10
  • kernel Rocky Linux 10 6.12.0-211.60.1.el10_2

rocky linux advisories RLSA-2026:75746RLSA-2026:75747RLSA-2026:71602

  • kernel Azure Linux 3.0 6.6.157.1-1

azure linux advisories AZL-100646

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

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-2026-89481 updated cvss 7.1

kernel: nvme-tcp: fix host memory disclosure on R2T for a read command

  • 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 Red Hat OpenShift Container Platform 4 openshift/ose-rhel-coreos-8 Red Hat OpenShift Container Platform 5 openshift/ose-rhel-coreos-9
    affected: workaround, no fix available
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-687.55.1.el9_8, perf 5.14.0-687.55.1.el9_8, rtla 5.14.0-687.55.1.el9_8, python3-perf 5.14.0-687.55.1.el9_8, kernel-devel-matched 5.14.0-687.55.1.el9_8, kernel-64k-devel-matched 5.14.0-687.55.1.el9_8, +7 more
    fixed: vendor fix RHSA-2026:76739
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.60.1.el10_2, perf 6.12.0-211.60.1.el10_2, rtla 6.12.0-211.60.1.el10_2, python3-perf 6.12.0-211.60.1.el10_2, kernel-devel-matched 6.12.0-211.60.1.el10_2, kernel-64k-devel-matched 6.12.0-211.60.1.el10_2, +7 more
    fixed: vendor fix RHSA-2026:71602
  • 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 4.18.0-553.171.1.el8_10, kernel 4.18.0-553.171.1.el8_10, bpftool 4.18.0-553.171.1.el8_10, kernel-core 4.18.0-553.171.1.el8_10, kernel-tools 4.18.0-553.171.1.el8_10, python3-perf 4.18.0-553.171.1.el8_10, +15 more
    fixed: vendor fix RHSA-2026:75747
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-687.55.1.el9_8, kernel-64k 5.14.0-687.55.1.el9_8, kernel-core 5.14.0-687.55.1.el9_8, kernel-tools 5.14.0-687.55.1.el9_8, kernel-modules 5.14.0-687.55.1.el9_8, kernel-64k-core 5.14.0-687.55.1.el9_8, +27 more
    fixed: vendor fix RHSA-2026:76739
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.60.1.el10_2, kernel-64k 6.12.0-211.60.1.el10_2, kernel-core 6.12.0-211.60.1.el10_2, kernel-tools 6.12.0-211.60.1.el10_2, kernel-modules 6.12.0-211.60.1.el10_2, kernel-64k-core 6.12.0-211.60.1.el10_2, +28 more
    fixed: vendor fix RHSA-2026:71602
show 20 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 5.14.0-687.55.1.el9_8, kernel-debuginfo-common-s390x 5.14.0-687.55.1.el9_8, kernel-debuginfo-common-x86_64 5.14.0-687.55.1.el9_8, kernel-debuginfo-common-aarch64 5.14.0-687.55.1.el9_8, kernel-debuginfo-common-ppc64le 5.14.0-687.55.1.el9_8
    fixed: vendor fix RHSA-2026:76739
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.60.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.60.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.60.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.60.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.60.1.el10_2
    fixed: vendor fix RHSA-2026:71602
  • 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 4.18.0-553.171.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.171.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.171.1.el8_10
    fixed: vendor fix RHSA-2026:75747
  • Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-553.171.1.rt7.512.el8_10, kernel-rt-kvm 4.18.0-553.171.1.rt7.512.el8_10, kernel-rt-core 4.18.0-553.171.1.rt7.512.el8_10, kernel-rt-modules 4.18.0-553.171.1.rt7.512.el8_10, kernel-rt-debug-kvm 4.18.0-553.171.1.rt7.512.el8_10, kernel-rt-debug-core 4.18.0-553.171.1.rt7.512.el8_10, +4 more
    fixed: vendor fix RHSA-2026:75746
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-687.55.1.el9_8, kernel-rt-64k 5.14.0-687.55.1.el9_8, kernel-rt-core 5.14.0-687.55.1.el9_8, kernel-rt-modules 5.14.0-687.55.1.el9_8, kernel-rt-64k-core 5.14.0-687.55.1.el9_8, kernel-rt-debug-core 5.14.0-687.55.1.el9_8, +14 more
    fixed: vendor fix RHSA-2026:76739
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.60.1.el10_2, kernel-rt-64k 6.12.0-211.60.1.el10_2, kernel-rt-core 6.12.0-211.60.1.el10_2, kernel-rt-modules 6.12.0-211.60.1.el10_2, kernel-rt-64k-core 6.12.0-211.60.1.el10_2, kernel-rt-debug-core 6.12.0-211.60.1.el10_2, +14 more
    fixed: vendor fix RHSA-2026:71602
  • 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 5.14.0-687.55.1.el9_8, kernel-rt-core 5.14.0-687.55.1.el9_8, kernel-rt-modules 5.14.0-687.55.1.el9_8, kernel-rt-debug-core 5.14.0-687.55.1.el9_8, kernel-rt-modules-core 5.14.0-687.55.1.el9_8, kernel-rt-debug-modules 5.14.0-687.55.1.el9_8, +4 more
    fixed: vendor fix RHSA-2026:76739
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.60.1.el10_2, kernel-rt-core 6.12.0-211.60.1.el10_2, kernel-rt-modules 6.12.0-211.60.1.el10_2, kernel-rt-debug-core 6.12.0-211.60.1.el10_2, kernel-rt-modules-core 6.12.0-211.60.1.el10_2, kernel-rt-debug-modules 6.12.0-211.60.1.el10_2, +4 more
    fixed: vendor fix RHSA-2026:71602
  • 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 4.18.0-553.171.1.rt7.512.el8_10, kernel-rt-core 4.18.0-553.171.1.rt7.512.el8_10, kernel-rt-modules 4.18.0-553.171.1.rt7.512.el8_10, kernel-rt-debug-core 4.18.0-553.171.1.rt7.512.el8_10, kernel-rt-debug-modules 4.18.0-553.171.1.rt7.512.el8_10, kernel-rt-modules-extra 4.18.0-553.171.1.rt7.512.el8_10, +2 more
    fixed: vendor fix RHSA-2026:75746
  • Red Hat OpenShift Container Platform 4.22 rhcos 4.22.9.8.202610241758
    fixed: vendor fix RHSA-2026:89197
  • 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
partial
Assessed
23 d ago

Exploit prediction

0.43% chance of exploitation in the next 30 days, higher than 37% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

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.