How severe is CVE-2021-43987?

CVE-2021-43987 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-43987 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (64th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-43987?

CVE-2021-43987 affects Myscada Mypro. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-43987?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-43987 published?

CVE-2021-43987 was published on 2021-12-23 and last updated on 2026-06-17.

CVE-2021-43987

CVE-2021-43987 is a critical-severity vulnerability in Myscada Mypro with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-912.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 1% (64th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-912
Affected product: Myscada Mypro
Published: 2021-12-23
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is 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.
How severe is CVE-2021-43987?: CVE-2021-43987 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-43987 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (64th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-43987?: CVE-2021-43987 affects Myscada Mypro. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-43987?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-43987 published?: CVE-2021-43987 was published on 2021-12-23 and last updated on 2026-06-17.

References

https://www.cisa.gov/uscert/ics/advisories/icsa-21-355-01

Affected products (1)

cpe:2.3:a:myscada:mypro:*:*:*:*:*:*:*:*

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