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Known exploited vulnerability

CVE-2021-26828

highCVSS 3.1 8.8In CISA KEVEPSS 39%Published · n/a

The short answer

CVE-2021-26828 affects n/a n/a and is rated high (CVSS 8.8). CISA added it to the Known Exploited Vulnerabilities catalog on 2025-12-03: attackers are using it, so patch it first. The vendor has linked a patch.

What it is

OpenPLC ScadaBR through 0.9.1 on Linux and through 1.12.4 on Windows allows remote authenticated users to upload and execute arbitrary JSP files via view_edit.shtm.

Weakness: CWE-434.

Severity

8.8 high

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

Exploited (CISA KEV)

Yes, since Dec 3, 2025

Federal due date Dec 24, 2025

EPSS, next 30 days

39%

Higher than 99% of scored CVEs

How it can be exploited

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

What CISA says to do

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Affected products

n/a. NVD's record lists the exact affected versions.

References

Questions

Is CVE-2021-26828 being exploited?

Yes. CISA added CVE-2021-26828 to its Known Exploited Vulnerabilities catalog on 2025-12-03, with a federal remediation due date of 2025-12-24.

How do I fix CVE-2021-26828?

CISA's required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

From NVD, CISA KEV, FIRST EPSS and OSV.dev, checked . Status on NVD: Analyzed. The description is NVD's text, quoted as published.

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