How severe is CVE-2021-47770?

CVE-2021-47770 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-47770 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (46th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2021-47770?

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

Does CVE-2021-47770 have an EU (EUVD) identifier?

Yes. CVE-2021-47770 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-3655.

When was CVE-2021-47770 published?

CVE-2021-47770 was published on 2026-01-21 and last updated on 2026-06-17.

CVE-2021-47770

CVE-2021-47770 is a high-severity vulnerability with a CVSS 3.x base score of 8.8. 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-94.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v4: 8.6
EPSS exploit prediction: 1% (46th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-3655
Weakness: CWE-94
Published: 2026-01-21
Last modified: 2026-06-17

Description

OpenPLC v3 contains an authenticated remote code execution vulnerability that allows attackers with valid credentials to inject malicious code through the hardware configuration interface. Attackers can upload a custom hardware layer with embedded reverse shell code that establishes a network connection to a specified IP and port, enabling remote command execution.

Frequently asked questions

What is CVE-2021-47770?: OpenPLC v3 contains an authenticated remote code execution vulnerability that allows attackers with valid credentials to inject malicious code through the hardware configuration interface. Attackers can upload a custom hardware layer with embedded reverse shell code that establishes a network connection to a specified IP and port, enabling remote command execution.
How severe is CVE-2021-47770?: CVE-2021-47770 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-47770 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (46th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2021-47770?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2021-47770 have an EU (EUVD) identifier?: Yes. CVE-2021-47770 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-3655.
When was CVE-2021-47770 published?: CVE-2021-47770 was published on 2026-01-21 and last updated on 2026-06-17.

References

Other CWE-94 (Code Injection) vulnerabilities

CVE-2026-57624 — Critical (CVSS 10.0): Unauthenticated Remote Code Execution (RCE) in Blocksy Companion Pro <= 2.1.46 versions.
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CVE-2026-10561 — Critical (CVSS 10.0): IBM Langflow OSS 1.0.0 through 1.9.3 has an vulnerability due to an improper isolation of Python execution combined…
CVE-2026-25470 — Critical (CVSS 10.0): Improper Control of Generation of Code ('Code Injection') vulnerability in ACPT ACPT (Pro) - Custom Post Types Plugin…
CVE-2026-48836 — Critical (CVSS 10.0): Unauthenticated Remote Code Execution (RCE) in Easy Invoice <= 2.1.19 versions.

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