What is CVE-2021-43987?

CVE-2021-43987 is a critical-severity vulnerability in Myscada Mypro, classified under Hidden Functionality. CVSS score: 9.8/10. Published 2021-12-23.

How severe is CVE-2021-43987?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Vulnerability in Myscada Mypro

CVE-2021-43987

An additional, nondocumented administrative account exists in mySCADA myPRO Versions 8.20.0 and prior that is not exposed through the web interface, which cannot be deleted or changed through the regular web interface.

Published 2021-12-23 · last modified 2026-06-17.

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.

EPSS exploit prediction

EPSS: 0.012 (66.3th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 66th percentile — 66.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.012 · newest: 0.012 · change: 0.000

Affected products

Myscada Mypro — versions All

Weakness classification (CWE)

CWE-912 — Hidden Functionality

References

www.cisa.gov/uscert/ics/advisories/icsa-21-355-01 (US Government Resource, Third Party Advisory)

Frequently asked questions

What is CVE-2021-43987?: CVE-2021-43987 is a critical-severity vulnerability in Myscada Mypro, classified under Hidden Functionality. CVSS score: 9.8/10. Published 2021-12-23.
How severe is CVE-2021-43987?: Critical severity. CVSS v3 base score is 9.8 out of 10.