---
id: CVE-2026-80586
title: |-
  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
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 …
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-824
vendor: Red Hat
product: Red Hat Enterprise Linux 9
affected:
  - enterprise_linux 10
  - enterprise_linux 8
  - enterprise_linux 9
  - enterprise_linux_baseos_v_8
  - enterprise_linux_crb_v_8
patched:
  - enterprise_linux_baseos_v_8
  - enterprise_linux_crb_v_8
published: '2026-08-26'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T20:18:01.740'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-80586'
references:
  - url: 'https://git.kernel.org/stable/c/15e35fdad7a5576bf3f1c8d688877aeb5d1b506b'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/192878df582c51d440bf7b91a15f297f29f2b596'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/1fade1b2ac5b1a4948e538fae7313bea57b5ac36'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/26dac5c9ffb20812b475fdf253eb04fab99cff3b'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/27ed642a4e7e4b5df4b8522c72c457a67e052493'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/35772b4981f38ba8059372cde8753e8e477e98ec'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/4e80eff5c1c893aca2ac1d202f0b256d2e52ecde'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/b1256090816ec46011601e084be580731df58fc7'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80586.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-80586'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2524438'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-80586'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-80586'
  - url: >-
      https://lore.kernel.org/linux-cve-announce/2026082616-CVE-2026-80586-008c@gregkh/T
  - url: 'https://access.redhat.com/errata/RHSA-2026:89083'
tags:
  - nvd
  - csaf
  - vex
  - red-hat
  - cve.org
epss: 0.00399
epssPercentile: 0.33956
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-10-16T19:17:59.284912Z'
scores:
  nvd: 9.8
  vendor: 8.3
  cna: 9.8
ingestedAt: '2026-10-16T19:46:24.312Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.

## Vendor advisories

- **RHSA-2026:89083** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS (v. 8), Red Hat Enterprise Linux CRB (v. 8) · released 2026-10-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:89083)
- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9 · updated 2026-10-26 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80586.json)