CVE-2021-26829

What the flaw is

OpenPLC ScadaBR contains a cross-site scripting vulnerability via system_settings.shtm.

Description as published by CISA. We have not independently reproduced it.

What CISA requires

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

This deadline is binding on US federal civilian agencies under BOD 22-01. It is not a legal deadline for anyone else, but it is a useful urgency signal — CISA sets it by how actively the flaw is being used, not by CVSS.

Public exploit code

1 public repository referencing this CVE has been catalogued on GitHub. Treat this as a strong signal to prioritise patching, not as a verified working exploit — many such repositories are scanners, write-ups or forks rather than functional code.

• ARPSyndicate/cve-scores

Vendor advisories

• github.com/SCADA-LTS/Scada-LTS/pull/3211
• nvd.nist.gov/vuln/detail/CVE-2021-26829

Primary sources

• NVD entry — CVSS score, CPE list and references
• CISA KEV catalog — the source for this page
• CVE Record at cve.org