Vulnerability record · CVE-2018-7791 · published 29 August 2018

CVE-2018-7791: Schneider-electric modicon m221 firmware improper authentication vulnerability

Schneider Electric · Modicon M221 Firmware

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.

9.8 CVSS 3.1 Critical EPSS 1.9% · top 21.2% CWE-287 · Improper authenticationCWE-284 · Improper access control

9.8CVSS 3.1 base score, v2 7.5

1.9%EPSS exploitation probability, 30 days

NoNot in CISA KEV

1Affected product versions listed by NVD

4References

17 Jun 2026Last modified by NVD

Description

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

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

Modicon M221 Firmware Schneider Electric

References

Link	Tags
http://www.securityfocus.com/bid/105182	Third Party AdvisoryVDB Entry
https://www.schneider-electric.com/en/download/document/SEVD-2018-235-01/	MitigationVendor Advisory
http://www.securityfocus.com/bid/105182	Third Party AdvisoryVDB Entry
https://www.schneider-electric.com/en/download/document/SEVD-2018-235-01/	MitigationVendor Advisory

Track CVE-2018-7791 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2020-7489Schneider-electric ecostruxure machine expert injection vulnerabilityA CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection') vulnerability exists on EcoStruxure Mach…EPSS 1.6%22 Apr 2020 9.8CVE-2018-7790Schneider-electric modicon m221 firmware authentication bypass by capture-replay vulnerabilityAn Information Management Error vulnerability exists in Schneider Electric's Modicon M221 product (all references, all versions prior to firmware V1.…EPSS 2.5%29 Aug 2018 8.2CVE-2019-6820Schneider-electric modicon m100 firmware missing authentication for critical function vulnerabilityA CWE-306: Missing Authentication for Critical Function vulnerability exists which could cause a modification of device IP configuration (IP address,…EPSS 1.3%22 May 2019 7.5CVE-2018-7821Schneider-electric somachine basic allocation without limits vulnerabilityAn Environment (CWE-2) vulnerability exists in SoMachine Basic, all versions, and Modicon M221(all references, all versions prior to firmware V1.10.0…EPSS 1.1%22 May 2019 7.5CVE-2019-10953Abb pm554-tp-eth firmware uncontrolled resource consumption vulnerabilityABB, Phoenix Contact, Schneider Electric, Siemens, WAGO - Programmable Logic Controllers, multiple versions. Researchers have found some controllers …EPSS 3.4%17 Apr 2019 7.5CVE-2018-7792Schneider-electric modicon m221 firmware missing authorization vulnerabilityA Permissions, Privileges, and Access Control vulnerability exists in Schneider Electric's Modicon M221 product (all references, all versions prior t…EPSS 1.1%29 Aug 2018 7.5CVE-2018-7789Schneider-electric modicon m221 firmware vulnerabilityAn Improper Check for Unusual or Exceptional Conditions vulnerability exists in Schneider Electric's Modicon M221 product (all references, all versio…EPSS 2.8%29 Aug 2018 7.3CVE-2020-7566Schneider-electric modicon m221 firmware vulnerabilityA CWE-334: Small Space of Random Values vulnerability exists in Modicon M221 (all references, all versions) that could allow the attacker to break th…EPSS 0.30%19 Nov 2020

Source: NIST National Vulnerability Database (record CVE-2018-7791), CISA KEV, FIRST EPSS (scores of 2026-09-28). This page is refreshed as NVD updates the record.