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Fencer Vulns
critical 9.8

CVE-2026-89526 in the critical feed json

svcrdma: Validate Read chunk positions before reconstruction

published 2026-09-11 58 d ago modified 2026-10-30 10 d ago also EUVD-2026-76432

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.7%
EPSS 0.7% chance of exploitation in 30 days, percentile 52%
public exploits
0
none known

Summary

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

svcrdma: Validate Read chunk positions before reconstruction

The RPC/RDMA Read chunk position field is supplied by the remote client and stored verbatim in the parsed chunk list. xdr_count_read_segments() checks only 4-byte alignment; it never compares the position against the received inline body length.

In the single-chunk path, svc_rdma_read_complete_one() splits the head and tail kvecs at ch_position. A position past the inline body underflows the tail length, exposing adjacent slab memory to the upper XDR decoder.

In the multi-chunk path, svc_rdma_read_multiple_chunks() computes gap lengths between chunks as unsigned subtractions from ch_position. Overlapping Read chunks cause these subtractions to underflow. A final position past the inline body likewise underflows the trailing gap length. svc_rdma_copy_inline_range() then copies past the receive buffer into request pages that are returned to the client through the Reply channel.

Bound inline-range copies in svc_rdma_copy_inline_range() against the decoded inline RPC body saved in rc_saved_arg. Reject a single Read chunk positioned beyond that body, and reject multi-chunk lists where accumulated read bytes exceed the next chunk's position. Apply the same position and overlap checks in the call-chunk interleaving path.

Patch / fix

  • Linux Linux 6.1.191, 6.6.160, 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-2026-89526

  • 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-2026-89526

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 6.12.0-211.66.1.el10_2
  • rv RHEL 10.2 6.12.0-211.66.1.el10_2
  • perf RHEL 10.2 6.12.0-211.66.1.el10_2
  • rtla RHEL 10.2 6.12.0-211.66.1.el10_2
  • libperf RHEL 10.2 6.12.0-211.66.1.el10_2
  • kernel-rt RHEL 10.2 6.12.0-211.66.1.el10_2
  • kernel-64k RHEL 10.2 6.12.0-211.66.1.el10_2
  • kernel-core RHEL 10.2 6.12.0-211.66.1.el10_2

red hat advisories RHSA-2026:83207RHSA-2026:83157RHSA-2026:83159RHSA-2026:83156

  • kernel-default SLES 16.0, SLE High Availability Extension 16.0, Linux Micro 6.2 +1 more 6.12.0-160000.39.1
  • kernel-rt Linux Micro 6.2 6.12.0-160000.39.1
  • kernel-64kb SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.39.1
  • kernel-source SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.39.1
  • kernel-default-base SLES 16.0, Linux Micro 6.2, SLES for SAP applications 16.0 6.12.0-160000.39.1.160000.2.26
  • kernel-syms SLES 16.0, Linux Micro Extras 6.2, SLES for SAP applications 16.0 6.12.0-160000.39.1
  • kernel-azure SLES for SAP applications 16.0, SLES 16.0 6.12.0-160000.39.1
  • kernel-obs-qa SLES for SAP applications 16.0, SLES 16.0 6.12.0-160000.39.1

suse advisories SUSE-SU-2026:24197-1SUSE-SU-2026:24184-1SUSE-SU-2026:24235-1SUSE-SU-2026:24179-1

  • 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 AlmaLinux 9 5.14.0-687.58.1.el9_8
  • rv AlmaLinux 9 5.14.0-687.58.1.el9_8
  • perf AlmaLinux 9 5.14.0-687.58.1.el9_8
  • rtla AlmaLinux 9 5.14.0-687.58.1.el9_8
  • libperf AlmaLinux 9 5.14.0-687.58.1.el9_8
  • kernel-rt AlmaLinux 9 5.14.0-687.58.1.el9_8
  • kernel-64k AlmaLinux 9 5.14.0-687.58.1.el9_8
  • kernel-core AlmaLinux 9 5.14.0-687.58.1.el9_8

almalinux advisories ALSA-2026:83156ALSA-2026:83157ALSA-2026:83159ALSA-2026:83207

  • kernel Rocky Linux 10 6.12.0-211.66.1.el10_2
  • kernel Rocky Linux 9 5.14.0-687.58.1.el9_8
  • kernel-rt Rocky Linux 8 4.18.0-553.174.1.rt7.515.el8_10
  • kernel Rocky Linux 8 4.18.0-553.174.1.el8_10

rocky linux advisories RLSA-2026:83207RLSA-2026:83156RLSA-2026:83159RLSA-2026:83157

  • kernel Azure Linux 3.0 6.6.161.1-1

azure linux advisories AZL-100728

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-2026-89526 updated cvss 8.1

kernel: svcrdma: Validate Read chunk positions before reconstruction

  • 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 kernel-modules-internal 6.12.0-211.66.1.el10_2
    fixed: vendor fix RHSA-2026:83207
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-687.58.1.el9_8, perf 5.14.0-687.58.1.el9_8, rtla 5.14.0-687.58.1.el9_8, python3-perf 5.14.0-687.58.1.el9_8, kernel-devel-matched 5.14.0-687.58.1.el9_8, kernel-64k-devel-matched 5.14.0-687.58.1.el9_8, +7 more
    fixed: vendor fix RHSA-2026:83156
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.66.1.el10_2, perf 6.12.0-211.66.1.el10_2, rtla 6.12.0-211.66.1.el10_2, python3-perf 6.12.0-211.66.1.el10_2, kernel-devel-matched 6.12.0-211.66.1.el10_2, kernel-64k-devel-matched 6.12.0-211.66.1.el10_2, +7 more
    fixed: vendor fix RHSA-2026:83207
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.174.1.el8_10, kernel 4.18.0-553.174.1.el8_10, bpftool 4.18.0-553.174.1.el8_10, kernel-core 4.18.0-553.174.1.el8_10, kernel-tools 4.18.0-553.174.1.el8_10, python3-perf 4.18.0-553.174.1.el8_10, +15 more
    fixed: vendor fix RHSA-2026:83157
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-687.58.1.el9_8, kernel-64k 5.14.0-687.58.1.el9_8, kernel-core 5.14.0-687.58.1.el9_8, kernel-tools 5.14.0-687.58.1.el9_8, kernel-modules 5.14.0-687.58.1.el9_8, kernel-64k-core 5.14.0-687.58.1.el9_8, +27 more
    fixed: vendor fix RHSA-2026:83156
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.66.1.el10_2, kernel-64k 6.12.0-211.66.1.el10_2, kernel-core 6.12.0-211.66.1.el10_2, kernel-tools 6.12.0-211.66.1.el10_2, kernel-modules 6.12.0-211.66.1.el10_2, kernel-64k-core 6.12.0-211.66.1.el10_2, +28 more
    fixed: vendor fix RHSA-2026:83207
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-687.58.1.el9_8, kernel-debuginfo-common-s390x 5.14.0-687.58.1.el9_8, kernel-debuginfo-common-x86_64 5.14.0-687.58.1.el9_8, kernel-debuginfo-common-aarch64 5.14.0-687.58.1.el9_8, kernel-debuginfo-common-ppc64le 5.14.0-687.58.1.el9_8
    fixed: vendor fix RHSA-2026:83156
show 10 more
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.66.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.66.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.66.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.66.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.66.1.el10_2
    fixed: vendor fix RHSA-2026:83207
  • Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.174.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.174.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.174.1.el8_10
    fixed: vendor fix RHSA-2026:83157
  • Red Hat Enterprise Linux Hidden (v. 10) kernel-modules-internal 6.12.0-211.66.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.66.1.el10_2
    fixed: vendor fix RHSA-2026:83207
  • Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-553.174.1.rt7.515.el8_10, kernel-rt-kvm 4.18.0-553.174.1.rt7.515.el8_10, kernel-rt-core 4.18.0-553.174.1.rt7.515.el8_10, kernel-rt-modules 4.18.0-553.174.1.rt7.515.el8_10, kernel-rt-debug-kvm 4.18.0-553.174.1.rt7.515.el8_10, kernel-rt-debug-core 4.18.0-553.174.1.rt7.515.el8_10, +4 more
    fixed: vendor fix RHSA-2026:83159
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-687.58.1.el9_8, kernel-rt-64k 5.14.0-687.58.1.el9_8, kernel-rt-core 5.14.0-687.58.1.el9_8, kernel-rt-modules 5.14.0-687.58.1.el9_8, kernel-rt-64k-core 5.14.0-687.58.1.el9_8, kernel-rt-debug-core 5.14.0-687.58.1.el9_8, +14 more
    fixed: vendor fix RHSA-2026:83156
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.66.1.el10_2, kernel-rt-64k 6.12.0-211.66.1.el10_2, kernel-rt-core 6.12.0-211.66.1.el10_2, kernel-rt-modules 6.12.0-211.66.1.el10_2, kernel-rt-64k-core 6.12.0-211.66.1.el10_2, kernel-rt-debug-core 6.12.0-211.66.1.el10_2, +14 more
    fixed: vendor fix RHSA-2026:83207
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-687.58.1.el9_8, kernel-rt-core 5.14.0-687.58.1.el9_8, kernel-rt-modules 5.14.0-687.58.1.el9_8, kernel-rt-debug-core 5.14.0-687.58.1.el9_8, kernel-rt-modules-core 5.14.0-687.58.1.el9_8, kernel-rt-debug-modules 5.14.0-687.58.1.el9_8, +4 more
    fixed: vendor fix RHSA-2026:83156
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.66.1.el10_2, kernel-rt-core 6.12.0-211.66.1.el10_2, kernel-rt-modules 6.12.0-211.66.1.el10_2, kernel-rt-debug-core 6.12.0-211.66.1.el10_2, kernel-rt-modules-core 6.12.0-211.66.1.el10_2, kernel-rt-debug-modules 6.12.0-211.66.1.el10_2, +4 more
    fixed: vendor fix RHSA-2026:83207
  • Red Hat Enterprise Linux RT (v. 8) kernel-rt 4.18.0-553.174.1.rt7.515.el8_10, kernel-rt-core 4.18.0-553.174.1.rt7.515.el8_10, kernel-rt-modules 4.18.0-553.174.1.rt7.515.el8_10, kernel-rt-debug-core 4.18.0-553.174.1.rt7.515.el8_10, kernel-rt-debug-modules 4.18.0-553.174.1.rt7.515.el8_10, kernel-rt-modules-extra 4.18.0-553.174.1.rt7.515.el8_10, +2 more
    fixed: vendor fix RHSA-2026:83159
  • 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

0.68% chance of exploitation in the next 30 days, higher than 52% 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.