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Fencer Vulns
critical 9.8

CVE-2026-80586 in the critical feed json

mptcp: options: reset DSS fields in case of unexpected size

published 2026-08-26 2 mo ago modified 2026-10-16 23 d ago also EUVD-2026-66501

cvss
9.8
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 34%
public exploits
0
none known

Summary

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

mptcp: options: reset DSS fields in case of unexpected size

A remote peer could send a malformed DSS with a wrong size, followed by another DSS or MPC + Data. In this case, the first suboption will be ignored, but leaving some fields written, which could lead to inconsistency or access uninitialized data.

Explicitly reset the fields that could have been modified in case of unexpected size.

Patch / fix

  • Linux Linux 5.10.266, 5.15.217, 6.1.184, 6.6.153, 6.12.105, 6.18.46, 7.1.10, 7.2
  • linux Debian 12 6.1.187-1
  • linux Debian 13 6.12.105-1
  • linux Debian 14 7.1.10-1
  • linux-6.12 Debian 12 6.12.107-1~deb12u1

debian advisories DEBIAN-CVE-2026-80586

  • linux Ubuntu 22.04 LTS 5.15.0-202.212
  • linux Ubuntu 26.04 LTS 7.0.0-42.42
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1119.126
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1016.17
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1120.130
  • linux-gcp Ubuntu 26.04 LTS 7.0.0-1016.18
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1115.121
  • linux-ibm Ubuntu 22.04 LTS 5.15.0-1113.117

ubuntu advisories UBUNTU-CVE-2026-80586

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 6.12.0-160000.38.1
  • 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-rt AlmaLinux 8 4.18.0-553.178.1.rt7.519.el8_10
  • kernel-rt-core AlmaLinux 8 4.18.0-553.178.1.rt7.519.el8_10
  • kernel-rt-modules AlmaLinux 8 4.18.0-553.178.1.rt7.519.el8_10
  • kernel-rt-debug-core AlmaLinux 8 4.18.0-553.178.1.rt7.519.el8_10
  • kernel-rt-debug-modules AlmaLinux 8 4.18.0-553.178.1.rt7.519.el8_10
  • kernel-rt-modules-extra AlmaLinux 8 4.18.0-553.178.1.rt7.519.el8_10
  • kernel-rt-debug-modules-extra AlmaLinux 8 4.18.0-553.178.1.rt7.519.el8_10
  • kernel AlmaLinux 8 4.18.0-553.178.1.el8_10

almalinux advisories ALSA-2026:89082ALSA-2026:89083

  • kernel Rocky Linux 10 6.12.0-211.72.1.el10_2
  • kernel Rocky Linux 9 5.14.0-687.64.1.el9_8
  • kernel-rt Rocky Linux 8 4.18.0-553.178.1.rt7.519.el8_10
  • kernel Rocky Linux 8 4.18.0-553.178.1.el8_10

rocky linux advisories RLSA-2026:93413RLSA-2026:93412RLSA-2026:89082RLSA-2026:89083

  • kernel Azure Linux 3.0 6.6.157.1-1

azure linux advisories AZL-97776

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-2026-80586 updated cvss 8.3

kernel: mptcp: options: reset DSS fields in case of unexpected size

  • 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 6.12.0-211.72.1.el10_2
    fixed: vendor fix RHSA-2026:93413
  • Red Hat Enterprise Linux AppStream (v. 9) rv 5.14.0-687.64.1.el9_8, perf 5.14.0-687.64.1.el9_8, rtla 5.14.0-687.64.1.el9_8, python3-perf 5.14.0-687.64.1.el9_8, kernel-devel-matched 5.14.0-687.64.1.el9_8, kernel-64k-devel-matched 5.14.0-687.64.1.el9_8, +7 more
    fixed: vendor fix RHSA-2026:93412
  • Red Hat Enterprise Linux AppStream (v. 10) rv 6.12.0-211.72.1.el10_2, perf 6.12.0-211.72.1.el10_2, rtla 6.12.0-211.72.1.el10_2, python3-perf 6.12.0-211.72.1.el10_2, kernel-devel-matched 6.12.0-211.72.1.el10_2, kernel-64k-devel-matched 6.12.0-211.72.1.el10_2, +7 more
    fixed: vendor fix RHSA-2026:93413
  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.178.1.el8_10, kernel 4.18.0-553.178.1.el8_10, bpftool 4.18.0-553.178.1.el8_10, kernel-core 4.18.0-553.178.1.el8_10, kernel-tools 4.18.0-553.178.1.el8_10, python3-perf 4.18.0-553.178.1.el8_10, +15 more
    fixed: vendor fix RHSA-2026:89083
  • Red Hat Enterprise Linux BaseOS (v. 9) kernel 5.14.0-687.64.1.el9_8, kernel-64k 5.14.0-687.64.1.el9_8, kernel-core 5.14.0-687.64.1.el9_8, kernel-tools 5.14.0-687.64.1.el9_8, kernel-modules 5.14.0-687.64.1.el9_8, kernel-64k-core 5.14.0-687.64.1.el9_8, +27 more
    fixed: vendor fix RHSA-2026:93412
  • Red Hat Enterprise Linux BaseOS (v. 10) kernel 6.12.0-211.72.1.el10_2, kernel-64k 6.12.0-211.72.1.el10_2, kernel-core 6.12.0-211.72.1.el10_2, kernel-tools 6.12.0-211.72.1.el10_2, kernel-modules 6.12.0-211.72.1.el10_2, kernel-64k-core 6.12.0-211.72.1.el10_2, +28 more
    fixed: vendor fix RHSA-2026:93413
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 9) libperf 5.14.0-687.64.1.el9_8, kernel-debuginfo-common-s390x 5.14.0-687.64.1.el9_8, kernel-debuginfo-common-x86_64 5.14.0-687.64.1.el9_8, kernel-debuginfo-common-aarch64 5.14.0-687.64.1.el9_8, kernel-debuginfo-common-ppc64le 5.14.0-687.64.1.el9_8
    fixed: vendor fix RHSA-2026:93412
show 10 more
  • Red Hat Enterprise Linux CodeReady Linux Builder (v. 10) libperf 6.12.0-211.72.1.el10_2, kernel-debuginfo-common-s390x 6.12.0-211.72.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.72.1.el10_2, kernel-debuginfo-common-aarch64 6.12.0-211.72.1.el10_2, kernel-debuginfo-common-ppc64le 6.12.0-211.72.1.el10_2
    fixed: vendor fix RHSA-2026:93413
  • Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.178.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.178.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.178.1.el8_10
    fixed: vendor fix RHSA-2026:89083
  • Red Hat Enterprise Linux Hidden (v. 10) kernel-modules-internal 6.12.0-211.72.1.el10_2, kernel-debuginfo-common-x86_64 6.12.0-211.72.1.el10_2
    fixed: vendor fix RHSA-2026:93413
  • Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-553.178.1.rt7.519.el8_10, kernel-rt-kvm 4.18.0-553.178.1.rt7.519.el8_10, kernel-rt-core 4.18.0-553.178.1.rt7.519.el8_10, kernel-rt-modules 4.18.0-553.178.1.rt7.519.el8_10, kernel-rt-debug-kvm 4.18.0-553.178.1.rt7.519.el8_10, kernel-rt-debug-core 4.18.0-553.178.1.rt7.519.el8_10, +4 more
    fixed: vendor fix RHSA-2026:89082
  • Red Hat Enterprise Linux Real Time (v. 9) kernel-rt 5.14.0-687.64.1.el9_8, kernel-rt-64k 5.14.0-687.64.1.el9_8, kernel-rt-core 5.14.0-687.64.1.el9_8, kernel-rt-modules 5.14.0-687.64.1.el9_8, kernel-rt-64k-core 5.14.0-687.64.1.el9_8, kernel-rt-debug-core 5.14.0-687.64.1.el9_8, +14 more
    fixed: vendor fix RHSA-2026:93412
  • Red Hat Enterprise Linux Real Time (v. 10) kernel-rt 6.12.0-211.72.1.el10_2, kernel-rt-64k 6.12.0-211.72.1.el10_2, kernel-rt-core 6.12.0-211.72.1.el10_2, kernel-rt-modules 6.12.0-211.72.1.el10_2, kernel-rt-64k-core 6.12.0-211.72.1.el10_2, kernel-rt-debug-core 6.12.0-211.72.1.el10_2, +14 more
    fixed: vendor fix RHSA-2026:93413
  • Red Hat Enterprise Linux Real Time for NFV (v. 9) kernel-rt 5.14.0-687.64.1.el9_8, kernel-rt-core 5.14.0-687.64.1.el9_8, kernel-rt-modules 5.14.0-687.64.1.el9_8, kernel-rt-debug-core 5.14.0-687.64.1.el9_8, kernel-rt-modules-core 5.14.0-687.64.1.el9_8, kernel-rt-debug-modules 5.14.0-687.64.1.el9_8, +4 more
    fixed: vendor fix RHSA-2026:93412
  • Red Hat Enterprise Linux Real Time for NFV (v. 10) kernel-rt 6.12.0-211.72.1.el10_2, kernel-rt-core 6.12.0-211.72.1.el10_2, kernel-rt-modules 6.12.0-211.72.1.el10_2, kernel-rt-debug-core 6.12.0-211.72.1.el10_2, kernel-rt-modules-core 6.12.0-211.72.1.el10_2, kernel-rt-debug-modules 6.12.0-211.72.1.el10_2, +4 more
    fixed: vendor fix RHSA-2026:93413
  • Red Hat Enterprise Linux RT (v. 8) kernel-rt 4.18.0-553.178.1.rt7.519.el8_10, kernel-rt-core 4.18.0-553.178.1.rt7.519.el8_10, kernel-rt-modules 4.18.0-553.178.1.rt7.519.el8_10, kernel-rt-debug-core 4.18.0-553.178.1.rt7.519.el8_10, kernel-rt-debug-modules 4.18.0-553.178.1.rt7.519.el8_10, kernel-rt-modules-extra 4.18.0-553.178.1.rt7.519.el8_10, +2 more
    fixed: vendor fix RHSA-2026:89082
  • 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

0.40% chance of exploitation in the next 30 days, higher than 34% 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.