How severe is CVE-2019-18261?

CVE-2019-18261 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2019-18261 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (67th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-18261?

CVE-2019-18261 primarily affects Omron Plc Cj Firmware. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2019-18261?

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-2019-18261 published?

CVE-2019-18261 was published on 2019-12-16 and last updated on 2026-06-17.

CVE-2019-18261

CVE-2019-18261 is a critical-severity vulnerability in Omron Plc Cj Firmware with a CVSS 3.x base score of 9.8. 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-307.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 5.0
EPSS exploit prediction: 1% (67th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-307
Affected product: Omron Plc Cj Firmware
Published: 2019-12-16
Last modified: 2026-06-17

Description

In Omron PLC CS series, all versions, Omron PLC CJ series, all versions, and Omron PLC NJ series, all versions, the software does not implement sufficient measures to prevent multiple failed authentication attempts within in a short time frame, making it more susceptible to brute force attacks.

Frequently asked questions

What is CVE-2019-18261?: In Omron PLC CS series, all versions, Omron PLC CJ series, all versions, and Omron PLC NJ series, all versions, the software does not implement sufficient measures to prevent multiple failed authentication attempts within in a short time frame, making it more susceptible to brute force attacks.
How severe is CVE-2019-18261?: CVE-2019-18261 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2019-18261 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (67th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-18261?: CVE-2019-18261 primarily affects Omron Plc Cj Firmware. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2019-18261?: 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-2019-18261 published?: CVE-2019-18261 was published on 2019-12-16 and last updated on 2026-06-17.

References

https://www.us-cert.gov/ics/advisories/icsa-19-346-03

Affected products (3)

cpe:2.3:o:omron:plc_cj_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:omron:plc_cs_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:omron:plc_nj_firmware:*:*:*:*:*:*:*:*

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