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Fencer Vulns
critical 9.1

CVE-2023-0811 json

Omron CJ1M unit v4.0 and prior has improper access controls on the memory region where the UM password is stored.

published 2023-03-16 3 y ago modified 2026-06-17 4 mo ago also EUVD-2023-12816

cvss
9.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 50%
public exploits
0
none known

Summary

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.

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

cisa ICSA-23-073-01 updated cvss 9.1

Omron CJ1M PLC

  • Omron CJ1G-CPU □ □ P Omron CJ2H-CPU6 □ Omron CJ2H-CPU6 □ -EIP Omron CJ2M-CPU □ □ Omron CP1E-E □ □ D □ - □ Omron CP1E-NA □ □ D □ - □
    +17 more products
    Omron CP1H-X40D □ - □ Omron CP1H-XA40D □ - □ Omron CP1H-Y20DT-D Omron CP1L-EL20D □ - □ Omron CP1L-EM □ □ D □ - □ Omron CP1L-L □ □ D □- □ Omron CP1L-M □ □ D □ - □ Omron CP2E-E □ □ D □ - □ Omron CP2E-N □ □ D □ - □ Omron CP2E-S □ □ D □- □ Omron CS1D-CPU □ □ H Omron CS1D-CPU □ □ HA Omron CS1D-CPU □ □ P Omron CS1D-CPU □ □ S Omron CS1D-CPU □ □ SA Omron CS1G-CPU □ □ H Omron CS1H-CPU □ □ H
    affected: vendor fix

From CISA ICS and IT advisories (CSAF, https://github.com/cisagov/CSAF), a U.S. Government work; changed: reduced to products, statuses and remediations. CISA notification · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
21 mo ago

Exploit prediction

0.62% chance of exploitation in the next 30 days, higher than 50% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
NVD 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

Affected products

  • Omron CJ1M SYSMAC CJ-series
  • Omron CJ1M SYSMAC CS-series
  • Omron CJ1M SYSMAC CP-series

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.