---
id: CVE-2026-80993
title: >-
  kernel: net: phylink: correctly validate returned PCS in phylink_inband_caps
  (CVE-2026-80993)
summary: >-
  A flaw was found in the Linux kernel's `net: phylink` component. The
  `phylink_inband_caps()` function does not correctly validate the return value
  from `mac_select_pcs`, which can return an error pointer instead of a valid
  Physical Coding …
severity: medium
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
cvssSource: vendor
cwe: CWE-476
vendor: Red Hat
product: Red Hat Enterprise Linux 9
affected:
  - enterprise_linux 10
  - enterprise_linux 9
  - openshift_container_platform 4
published: '2026-09-11'
updated: '2026-09-14'
sourceUpdated: '2026-09-14T20:06:39+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80993.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80993.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-80993'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532314'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-80993'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-80993'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-80993.mbox
  - url: 'https://git.kernel.org/stable/c/b6b533f83461c3730875cf3ed5ff6362dcb67be9'
  - url: 'https://git.kernel.org/stable/c/fb4d77553841ae85bed9b2cf03351c401e871d85'
  - url: 'https://git.kernel.org/stable/c/f2849b1fd059ec9b3281b771e6ac5aad9feee851'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
epss: 0.00166
epssPercentile: 0.06252
ingestedAt: '2026-09-14T00:35:28.531Z'
---

## Overview

A flaw was found in the Linux kernel's `net: phylink` component. The `phylink_inband_caps()` function does not correctly validate the return value from `mac_select_pcs`, which can return an error pointer instead of a valid Physical Coding Sublayer (PCS) object. This oversight can lead to dereferencing an invalid pointer, causing a kernel panic. A kernel panic results in a system crash, leading to a Denial of Service (DoS).

## Vendor advisories

- **Red Hat VEX** · Low · affected: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · no fix planned: Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 9, Red Hat OpenShift Container Platform 4 · updated 2026-09-14 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80993.json)

**kernel: net: phylink: correctly validate returned PCS in phylink_inband_caps** — rated Low by Red Hat. Released 2026-09-11, updated 2026-09-14.

Affected:

- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4

No fix planned:

- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4

Not affected:

- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat OpenShift Container Platform 4

## Remediation

Fix deferred