Is CVE-2018-7791 in the CISA KEV catalog?

No. CVE-2018-7791 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2018-7791?

CVE-2018-7791 has a CVSS v3 base score of 9.8 (CRITICAL).

What is the EPSS score for CVE-2018-7791?

CVE-2018-7791 has an EPSS score of 1.90% (77th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2018-7791?

Upgrade modicon m221 firmware to 1.6.2.0 or later.

CVE & CISA-KEV Catalog

CVE-2018-7791

CRITICALEPSS 77th pctl

9.8

CVSS v3

NVD

Description

A Permissions, Privileges, and Access Control vulnerability exists in Schneider Electric's Modicon M221 product (all references, all versions prior to firmware V1.6.2.0). The vulnerability allows unauthorized users to overwrite the original password with their password. If an attacker exploits this vulnerability and overwrite the password, the attacker can upload the original program from the PLC.

CWE-287Improper Authentication CWE-284Improper Access Control

How to fix

Remediation Available

modicon m221 firmwareNVD

Affected:< 1.6.2.0Fixed in:1.6.2.0CVE-2018-7791derived 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

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Exploit Intelligence

1.90%probability of exploitation in 30 days

77thpercentile

Elevated risk: more likely to be exploited than 77% of all known CVEs.

References

Vendor Advisory1

schneider-electric.com

Third-Party Advisory1

securityfocus.com

Related Vulnerabilities

Other CWE-287 (Improper Authentication) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2023-35082	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2023-35078	Critical	9.8	100%	KEV + Ransom	Fix
CVE-2017-7921	Critical	9.8	100%	KEV	-
CVE-2024-7593	Critical	9.8	100%	KEV	-
CVE-2023-46805	High	8.2	100%	KEV + Ransom	-
CVE-2022-40684	Critical	9.8	100%	KEV + Ransom	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.