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Exploited vulnerability · CISA KEV

Is CVE-2021-26828 exploited? Yes: in CISA KEV since 3 Dec 2025

Gociux · OpenPLC ScadaBR · data: CISA KEV, CVE record, FIRST EPSS

Yes. CVE-2021-26828, OpenPLC ScadaBR Unrestricted Upload of File with Dangerous Type Vulnerability, is being exploited in the wild. CISA added it to its Known Exploited Vulnerabilities catalog on 3 Dec 2025, 1636 days after it was published. It affects OpenPLC ScadaBR. If you run it, CISA's required action is: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

exploitedYesCISA KEV · 3 Dec 2025
ransomwareNot knownno confirmed use
EPSStop 5%very likely to be exploited
severity8.8CVSS 3.1 · high
US federal due24 Dec 2025BOD 22-01 deadline

What it is

OpenPLC ScadaBR contains an unrestricted upload of file with dangerous type vulnerability that allows remote authenticated users to upload and execute arbitrary JSP files via view_edit.shtm.

VendorOpenPLC (2 exploited CVEs in KEV)
ProductScadaBR
VulnerabilityOpenPLC ScadaBR Unrestricted Upload of File with Dangerous Type Vulnerability
WeaknessCWE-434
Published11 Jun 2021
Added to KEV3 Dec 2025
Reported by (CNA)mitre

What to do

  1. Check whether you run it. Look for ScadaBR in your asset inventory, including appliances and cloud images. Stack check lists every exploited OpenPLC CVE at once.
  2. Apply the fix. Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
  3. If you can't patch today, take the affected service off the internet or restrict who can reach it, and check its logs for signs of compromise since 11 Jun 2021.
  4. Get told next time. Email alerts when CISA adds a CVE for OpenPLC.

Other exploited CVEs in ScadaBR

References

Questions

Is CVE-2021-26828 being exploited?

Yes. CISA added CVE-2021-26828 to the Known Exploited Vulnerabilities catalog on 3 Dec 2025, which means there is reliable evidence of exploitation in the wild.

Is CVE-2021-26828 used in ransomware attacks?

CISA does not list known ransomware use for it. That can change, and exploitation alone is reason to fix it first.

How do I fix CVE-2021-26828?

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. Check OpenPLC's advisory for the fixed versions, and if you can't patch quickly, restrict access to the affected ScadaBR and watch it for signs of compromise.

Sources: CISA KEV (exploitation, ransomware use, required action, due date), the CVE record (publication date, CVSS, CNA), NVD and FIRST EPSS (live score). More: all KEV additions in December 2025 · OpenPLC scorecard · act-now radar.

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