CVE-2021-26829 — OpenPLC ScadaBR Cross-site Scripting Vulnerability

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

01What is this vulnerability?

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

02Affected products

Vendor	Product	Versions
n	a / n/a	n/a

03Active exploitation status

Yes — actively exploited. Added to the CISA KEV catalog on 2025-11-28. Ransomware use: Unknown.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Open the Sigma generator with a pre-filled prompt for this CVE to draft a starting detection in your stack of choice:

Open in Sigma generator →

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2021-06-11T11:05:23.000Z
• Last modified: 2025-12-02T04:56:04.472Z
• Added to CISA KEV: 2025-11-28
• BOD 22-01 due: 2025-12-19

09References

• youtu.be — https://youtu.be/Xh6LPCiLMa8
• forum.scadabr.com.br — http://forum.scadabr.com.br/t/report-falhas-de-seguranca-em-versoes-do-scadabr/3…