Is CVE-2018-7821 in the CISA KEV catalog?

No. CVE-2018-7821 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2018-7821?

CVE-2018-7821 has a CVSS v3 base score of 7.5 (HIGH).

What is the EPSS score for CVE-2018-7821?

CVE-2018-7821 has an EPSS score of 1.10% (62th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2018-7821?

Upgrade modicon m221 firmware to 1.10.0.0 or later.

CVE & CISA-KEV Catalog

CVE-2018-7821

HIGH

7.5

CVSS v3

NVD

Description

An Environment (CWE-2) vulnerability exists in SoMachine Basic, all versions, and Modicon M221(all references, all versions prior to firmware V1.10.0.0) which could cause cycle time impact when flooding the M221 ethernet interface while the Ethernet/IP adapter is activated.

CWE-770Allocation of Resources Without Limits or Throttling CWE-400Resource Exhaustion

How to fix

Remediation Available

modicon m221 firmwareNVD

Affected:< 1.10.0.0Fixed in:1.10.0.0CVE-2018-7821derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploit Intelligence

1.10%probability of exploitation in 30 days

62ndpercentile

Moderate risk: more likely to be exploited than 62% of all known CVEs.

References

Vendor Advisory1

schneider-electric.com

Related Vulnerabilities

Other CWE-770 (Allocation of Resources Without Limits or Throttling) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2023-50387	High	7.5	100%	-	Fix
CVE-2019-11478	Medium	5.3	95%	-	Fix
CVE-2019-11479	High	7.5	92%	-	Fix
CVE-2024-27316	High	7.5	91%	-	Fix
CVE-2022-30522	High	7.5	90%	-	Fix
CVE-2019-9515	High	7.5	88%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-29.