How severe is CVE-2018-20818?

CVE-2018-20818 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-2018-20818 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (72nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-20818?

CVE-2018-20818 primarily affects Openplcproject Openplc V2 Firmware. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2018-20818?

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-2018-20818 published?

CVE-2018-20818 was published on 2019-04-22 and last updated on 2026-06-17.

CVE-2018-20818

CVE-2018-20818 is a critical-severity vulnerability in Openplcproject Openplc V2 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-119.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 2% (72nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-119
Affected product: Openplcproject Openplc V2 Firmware
Published: 2019-04-22
Last modified: 2026-06-17

Description

A buffer overflow vulnerability was discovered in the OpenPLC controller, in the OpenPLC_v2 and OpenPLC_v3 versions. It occurs in the modbus.cpp mapUnusedIO() function, which can cause a runtime crash of the PLC or possibly have unspecified other impact.

Frequently asked questions

What is CVE-2018-20818?: A buffer overflow vulnerability was discovered in the OpenPLC controller, in the OpenPLC_v2 and OpenPLC_v3 versions. It occurs in the modbus.cpp mapUnusedIO() function, which can cause a runtime crash of the PLC or possibly have unspecified other impact.
How severe is CVE-2018-20818?: CVE-2018-20818 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-2018-20818 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (72nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-20818?: CVE-2018-20818 primarily affects Openplcproject Openplc V2 Firmware. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-20818?: 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-2018-20818 published?: CVE-2018-20818 was published on 2019-04-22 and last updated on 2026-06-17.

References

https://arxiv.org/pdf/1809.07477

Affected products (2)

cpe:2.3:o:openplcproject:openplc_v2_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:openplcproject:openplc_v3_firmware:-:*:*:*:*:*:*:*

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