CVE-2026-82358: RT-Labs AB C-Open CANopen SDO Server Write Protection Bypass

Severity: medium (CVSS 6.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-01 · updated 2026-10-07
Weakness: CWE-863

Description

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.

Affected products

RT-Labs AB C-Open: before 1.1.1 — fixed in 1.1.1

How to fix

Upgrade to a fixed version: RT-Labs AB C-Open 1.1.1. Check the vendor advisory for mitigations.

References

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