TI-2018-05633 Aliases CVE-2018-7791 GHSA-ppc6-q8hw-556j

Improper access control in Schneider Electric Modicon M221, all references, all versions…

MEDIUM 53CWE-284Published 2018-08-29 · Updated 2026-05-29

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: Security bypass
Confidentiality · integrity · availability: High · High · High
Fix status: No fix listed

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA. Impact type from CWE-284.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.01872 79th percentileScored 2026-11-07

Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: Yes
Technical impact: Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
Schneider Electric	Modicon M221, all references, all versions prior to firmware V1.6.2.0	Modicon M221, all references, all versions prior to firmware V1.6.2.0	—	No fix listed	CNA

Modicon M221, all references, all versions prior to firmware V1.6.2.0 VendorSchneider Electric Affected Modicon M221, all references, all versions prior to firmware V1.6.2.0 Fixed in — No fix listed CNA

CPE configurations NVD · 2

CPE	Versions	Role	Vendor
cpe:2.3:o:schneider-electric:modicon_m221_firmware::::::::	before 1.6.2.0	Vulnerable	Schneider Electric
cpe:2.3:h:schneider-electric:modicon_m221:-:::::::*	not specified by NVD	Running on	Schneider Electric

cpe:2.3:o:schneider-electric:modicon_m221_firmware:*:*:*:*:*:*:*:* Versions before 1.6.2.0 Vulnerable ·Schneider Electric
cpe:2.3:h:schneider-electric:modicon_m221:-:*:*:*:*:*:*:* Versions not specified by NVD Running on ·Schneider Electric

Remediation

No fixed version listed by the sources yet.

Timeline

2026-10-02 Threatist record created from CVE-2018-7791
2026-10-03 Alias added: GHSA-ppc6-q8hw-556j

References

Advisory 1

https://www.schneider-electric.com/en/download/document/SEVD-2018-235-01/

TI-2018-05632 Authentication bypass by capture-replay in Schneider Electric Modicon M221, all… CVSS 3.1CRITICAL 9.8
TI-2020-06012 Injection in SoMachine Basic EcoStruxure Machine Expert – Basic Modicon M100 Logic… CVSS 3.1CRITICAL 9.8
TI-2020-17144 A CWE-760: Use of a One-Way Hash with a Predictable Salt vulnerability exists in Modicon… CVSS 3.1CRITICAL 9.8
TI-2019-08172 Uncontrolled resource consumption in ABB 1SAP120600R0071 PM554-TP-ETH CVSS 3.1HIGH 7.5
TI-2019-04853 Missing authentication in Modicon and PacDrive Controller, All versions of: Modicon M100… CVSS 3.1HIGH 8.2
TI-2018-05659 Uncontrolled resource consumption in SoMachine Basic and Modicon M221, SoMachine Basic… CVSS 3.1HIGH 7.5

See all 15 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences