CVE-2018-7791

Severity: critical (CVSS 9.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.9% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2018-08-29 · updated 2026-06-17
Weakness: CWE-287

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.

Affected products

Modicon M221, all references, all versions: before 1.6.2.0 — fixed in 1.6.2.0

How to fix

Upgrade to a fixed version: Modicon M221, all references, all versions 1.6.2.0. Check the vendor advisory for mitigations.

References

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