How severe is CVE-2023-0811?

CVE-2023-0811 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.

Is CVE-2023-0811 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (45th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2023-0811?

CVE-2023-0811 primarily affects Omron Sysmac Cj2h-cpu64 Firmware. In total, 128 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2023-0811?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2023-0811 published?

CVE-2023-0811 was published on 2023-03-16 and last updated on 2026-06-17.

CVE-2023-0811

CVE-2023-0811 is a critical-severity vulnerability in Omron Sysmac Cj2h-cpu64 Firmware with a CVSS 3.x base score of 9.1. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-284.

Key facts

Severity: Critical (CVSS 3.x base score 9.1)
EPSS exploit prediction: 1% (45th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-284
Affected product: Omron Sysmac Cj2h-cpu64 Firmware
Published: 2023-03-16
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2023-0811?: 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.
How severe is CVE-2023-0811?: CVE-2023-0811 has a CVSS 3.x base score of 9.1, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability high.
Is CVE-2023-0811 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (45th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2023-0811?: CVE-2023-0811 primarily affects Omron Sysmac Cj2h-cpu64 Firmware. In total, 128 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2023-0811?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2023-0811 published?: CVE-2023-0811 was published on 2023-03-16 and last updated on 2026-06-17.

References

Affected products (128)

cpe:2.3:o:omron:sysmac_cj2h-cpu64_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cj2h-cpu64-eip_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cj2h-cpu65_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cj2h-cpu65-eip_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cj2h-cpu66_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cj2h-cpu66-eip_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cj2h-cpu67_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cj2h-cpu67-eip_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cj2h-cpu68_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cj2h-cpu68-eip_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cj2m-cpu11_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cj2m-cpu12_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cj2m-cpu13_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cj2m-cpu14_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cj2m-cpu15_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cj2m-cpu31_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cj2m-cpu32_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cj2m-cpu33_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cj2m-cpu34_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cj2m-cpu35_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cp1e-e10dr-a_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cp1e-e10dr-d_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cp1e-e10dt-a_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cp1e-e10dt-d_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cp1e-e10dt1-a_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cp1e-e10dt1-d_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cp1e-e14dr-a_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cp1e-e14sdr-a_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cp1e-e20dr-a_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cp1e-e20sdr-a_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cp1e-e30dr-a_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cp1e-e30sdr-a_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cp1e-e40dr-a_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cp1e-e40sdr-a_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cp1e-e60sdr-a_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cp1e-na20dr-a_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cp1e-na20dt-d_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cp1e-na20dt1-d_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cp1h-x40dr-a_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:omron:sysmac_cp1h-x40dt-d_firmware:-:*:*:*:*:*:*:*

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