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Vulnerabilities

Vulnerability · CVE-2021-26829

OpenPLC ScadaBR Cross-site Scripting Vulnerability

Published Jun 11, 2021 · catalog updated Jun 16, 2026 · OpenPLC ScadaBR

Patch now

CVE-2021-26829 is in the CISA known-exploited catalog, due Dec 19, 2025. Confirm OpenPLC ScadaBR against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Gaps on this record

  • No version range is stored. A customer cannot check an installed version against this record.
Severity
Medium5.4
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
48.05%
Remediation
Remediation guidance
Affected products
cpe scadabr/scadabr · vendor OpenPLC ScadaBR

OpenPLC ScadaBR through 0.9.1 on Linux and through 1.12.4 on Windows allows stored XSS via system_settings.shtm.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe scadabr/scadabrversion unspecified
  • vendor OpenPLC ScadaBRversion unspecified

How to fix CVE-2021-26829

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2021-26829 is in the CISA known-exploited catalog, due Dec 19, 2025. Confirm OpenPLC ScadaBR against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Affected version ranges are not on this record. Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

What should an analyst verify?

CWE-79: Cross-site Scripting (XSS). EPSS 48.05%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Jun 11, 2021 · Catalog

    Detected

    OpenPLC ScadaBR through 0.9.1 on Linux and through 1.12.4 on Windows allows stored XSS via system_settings.shtm.

  2. Nov 28, 2025 · CISA KEV

    Known exploited

    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. Dec 19, 2025 · CISA KEV

    Remediation due

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

  4. Jun 16, 2026 · Catalog

    Updated

    OpenPLC ScadaBR through 0.9.1 on Linux and through 1.12.4 on Windows allows stored XSS via system_settings.shtm.

Sources

  • CISA KEVConfirmed exploitationCVE-2021-26829

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

    cisa.gov
  • CVE.orgVulnerability recordCVE-2021-26829

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2021-26829

    30-day exploitation probability 48.0%

    first.org
  • NIST NVDVulnerability recordCVE-2021-26829

    OpenPLC ScadaBR through 0.9.1 on Linux and through 1.12.4 on Windows allows stored XSS via system_settings.shtm.

    nvd.nist.gov
  • VulnCheck KEVConfirmed exploitationCVE-2021-26829

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

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 17, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.