IRONSMITHINTEL
MEDIUMCVSS5.4
|
Actively Exploited
|CISA KEV|CVE-2021-26829|Auth: low — authenticated user|Reboot: required|Manual only

OpenPLC ScadaBR Cross-site Scripting Vulnerability

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

Published Jun 11, 2021 · Updated May 16, 2026
Why patchRisk explained in plain English
Worst-case scenarioIf unpatched

A remote attacker, with a low-privilege account, can achieve partial data exposure, partial data tampering. Federal agencies are required to remediate by 2025-12-19 under CISA BOD 22-01.

How the attack worksNo clicks needed

This is a Cross-Site Scripting (XSS) (CWE-79) vulnerability in OpenPLC ScadaBR. Exploitation requires remote network access, low attack complexity, a low-privilege authenticated account, and user interaction required.

Am I affected?Quick check

Probably yes if any of these apply:

IT Security
Running scadabr: v ≤ 0.9.1, v ≤ 1.12.4
Real-world incidentsWhat we've seen

Active exploitation documented in the wild. Threat-research write-up: https://youtu.be/Xh6LPCiLMa8

How to patch

Manual remediation steps

Apply the Vendor Patch

This vulnerability is in the CISA Known Exploited Vulnerabilities catalog — apply the vendor's security update as soon as possible.

CISA 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.

References

    1
    Vendor advisory: http://forum.scadabr.com.br/t/report-falhas-de-seguranca-em-versoes-do-scadabr/3615/4
    1
    NVD entry: https://nvd.nist.gov/vuln/detail/CVE-2021-26829
    1
    CISA KEV: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26829
PowerShell automationComing soon

No tested PowerShell script for this entry yet. We’re prioritising automation based on user demand.