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CVE-2021-26829

OpenPLC ScadaBR Cross-site Scripting

5.4 MEDIUMActively exploited (CISA KEV)Public exploitEPSS 48.0%
  1. Published11 Jun 2021
  2. Added to CISA KEV28 Nov 2025
  3. Remediation due19 Dec 2025
Actively exploited (CISA KEV)

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

Added to KEV: 28 Nov 2025Federal remediation due: 19 Dec 2025

Description

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

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredLow
User interactionRequired
ScopeChanged
ConfidentialityLow
IntegrityLow
AvailabilityNone
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Affected products

Scadabr≤ 0.9.1 · ≤ 1.12.4

Remediation

No fixed version is recorded in the NVD data. Check the vendor advisory for the latest guidance.

References

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Frequently asked

Is CVE-2021-26829 being actively exploited?

Yes. CVE-2021-26829 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 28 Nov 2025.

How severe is CVE-2021-26829?

CVE-2021-26829 has a CVSS 3.1 base score of 5.4, rated medium. EPSS estimates a 48.0% probability of exploitation.

Which products are affected by CVE-2021-26829?

Affected products include Scadabr.

How do I fix CVE-2021-26829?

Apply the vendor's patch or advisory guidance, then verify no affected versions remain across your devices.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2021-26829 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. Because it is on the CISA KEV list, Secuno flags any affected asset as top-priority automatically. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.