CISA KEV · Known exploitedMedium

CVE-2021-26829

OpenPLC ScadaBR

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

CVSS
5.4
EPSS
48.0%
98.7% percentile
CISA KEV
Listed
Published
2021.06.11
PRIORITY ASSESSMENT

Immediate review

CISA has listed this vulnerability in the Known Exploited Vulnerabilities catalog.

Known exploitationConfirmed by CISA KEV
Exploit probability48.0%
Technical severityCVSS 5.4

Vulnerability overview

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

Affected product and versions

Product
OpenPLC ScadaBR
Affected versions
<= 0.9.1, <= 1.12.4
Fixed versions
No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
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.

Due date: 2025.12.19
  1. 1
    Identify

    Confirm that OpenPLC ScadaBR and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
CWE
CWE-79
KEV added
2025.11.28
Ransomware use
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