---
id: CVE-2026-82358
title: >-
  RT-Labs AB C-Open CANopen contains a write protection bypass in the SDO
  (Service Data Object) server implementation 'src/co_sdo_server.c' that fails
  to properly validate write permissions when processing download-segment frames
summary: >-
  RT-Labs AB C-Open CANopen contains a write protection bypass in the SDO
  (Service Data Object) server implementation 'src/co_sdo_server.c' that fails
  to properly validate write permissions when processing download-segment
  frames. An unaut…
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N'
cwe:
  - CWE-863
vendor: RT-Labs AB
product: C-Open
affected:
  - C-Open < 1.1.1
published: '2026-10-01'
updated: '2026-10-01'
sourceUpdated: '2026-10-01T20:34:45.250'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-82358'
references:
  - url: 'https://github.com/rtlabs-com/c-open/releases/tag/public%2Fv1.1.1'
    label: 9119a7d8-5eab-497f-8521-727c672e3725
  - url: >-
      https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/IT/white/2025/va-26-275-02.json
    label: 9119a7d8-5eab-497f-8521-727c672e3725
  - url: 'https://rt-labs.com/wp-content/uploads/2026/09/RRTL-260929-01.pdf'
    label: 9119a7d8-5eab-497f-8521-727c672e3725
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-82358'
    label: 9119a7d8-5eab-497f-8521-727c672e3725
tags:
  - nvd
  - cve.org
ingestedAt: '2026-10-01T19:58:57.563Z'
---

## Overview

RT-Labs AB C-Open CANopen contains a write protection bypass in the SDO (Service Data Object) server implementation 'src/co_sdo_server.c' that fails to properly validate write permissions when processing download-segment frames. An unauthenticated attacker on the CAN bus can initiate an SDO upload for a read-only Object Dictionary (OD) entry, which sets a data pointer to the read-only object, then send download-segment frames to write to that memory location. The download-segment handler does not verify that a download session is active, allowing any CANopen node to overwrite read-only OD entries using two SDO frames. Note that CANopen protocol operates over CAN bus and does not provide built-in authentication mechanisms. Fixed in 1.1.1.

## Remediation

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