---
id: CVE-2026-89721
title: 'phy: rockchip-samsung-dcphy: fix out-of-range max_register'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  phy: rockchip-samsung-dcphy: fix out-of-range max_register

  The PHY register block is 64KB, so with a register stride of 4 the
  last accessible register sits at offset 0…
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-125
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= b2a1a2ae7818c9d8da12bf7b1983c8b9f5fb712b <
    14afe18655c0951f4f85898f761bf92264e65ccd
  - >-
    Linux >= b2a1a2ae7818c9d8da12bf7b1983c8b9f5fb712b <
    c1a62f9dcf531d56c56da2e4435386b6d264c69f
  - >-
    Linux >= b2a1a2ae7818c9d8da12bf7b1983c8b9f5fb712b <
    4486e75ba647bd8b98fc1f053101b40caceeed4b
  - Linux 6.15
published: '2026-09-11'
updated: '2026-10-19'
sourceUpdated: '2026-10-19T08:51:33.997Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-89721'
references:
  - url: 'https://git.kernel.org/stable/c/14afe18655c0951f4f85898f761bf92264e65ccd'
  - url: 'https://git.kernel.org/stable/c/c1a62f9dcf531d56c56da2e4435386b6d264c69f'
  - url: 'https://git.kernel.org/stable/c/4486e75ba647bd8b98fc1f053101b40caceeed4b'
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89721.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89721'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532300'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89721'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89721'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89721.mbox
tags:
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.00206
epssPercentile: 0.10626
ingestedAt: '2026-09-14T11:11:19.885Z'
---

## Overview

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

phy: rockchip-samsung-dcphy: fix out-of-range max_register

The PHY register block is 64KB, so with a register stride of 4 the
last accessible register sits at offset 0xfffc. max_register names
0x10000, one register past the end of the mapping: dumping the
registers through the regmap debugfs interface reads beyond the
ioremapped region and oopses on the unmapped page. The oops fires
with the regmap lock held, so later PHY operations deadlock.

## Affected

- `Linux >= b2a1a2ae7818c9d8da12bf7b1983c8b9f5fb712b < 14afe18655c0951f4f85898f761bf92264e65ccd`
- `Linux >= b2a1a2ae7818c9d8da12bf7b1983c8b9f5fb712b < c1a62f9dcf531d56c56da2e4435386b6d264c69f`
- `Linux >= b2a1a2ae7818c9d8da12bf7b1983c8b9f5fb712b < 4486e75ba647bd8b98fc1f053101b40caceeed4b`
- `Linux 6.15`

## Remediation

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

## Vendor advisories

- **Red Hat VEX** · Moderate · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89721.json)