Lyrie
Critical CVE
CVSS 9.83 sources verified·1 min read
By Lyrie Threat Intelligence·5/29/2026

CRITICAL: CVE-2018-7791 (CVSS 9.8) — schneider-electric modicon m221 firmware

CVE: CVE-2018-7791

CVSS: 9.8 (3.1) — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Severity: CRITICAL

Status: Critical advisory

Affected

  • schneider-electric modicon m221 firmware
  • schneider-electric modicon m221

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.

Verified Sources

References

  • http://www.securityfocus.com/bid/105182
  • https://www.schneider-electric.com/en/download/document/SEVD-2018-235-01/
  • http://www.securityfocus.com/bid/105182
  • https://www.schneider-electric.com/en/download/document/SEVD-2018-235-01/

_Validated by the Lyrie Threat Intelligence Pipeline — 3 independent sources confirmed before publication. No speculation._

Lyrie Verdict

A vulnerability of this severity is exactly what Lyrie's anti-rogue-AI defense is built for: continuous, autonomous monitoring that doesn't wait for human reaction time.

Validated sources

  1. [1]NVD
  2. [2]GitHub Advisory
  3. [3]MITRE