Auth bypass in Schneider-Electric Modicon M221

CVE-2018-7791

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.

Vulnerability class: Broken Authentication

EPSS: 0.019 (78.2th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2018-7791?
CVE-2018-7791 is a critical-severity vulnerability in Schneider-Electric Modicon M221, classified under Improper Authentication. CVSS score: 9.8/10. Published 2018-08-29.
How severe is CVE-2018-7791?
Critical severity. CVSS v3 base score is 9.8 out of 10.