Is CVE-2021-26829 in the CISA KEV catalog?

Yes. CVE-2021-26829 is on the CISA Known Exploited Vulnerabilities list, added 2025-11-28.

What is the CVSS severity of CVE-2021-26829?

CVE-2021-26829 has a CVSS v3 base score of 5.4 (MEDIUM).

What is the EPSS score for CVE-2021-26829?

CVE-2021-26829 has an EPSS score of 48.05% (99th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2021-26829

MEDIUMCISA KEVEPSS 99th pctl

5.4

CVSS v3

NVD

Description

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

CWE-79Cross-Site Scripting (XSS)

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredLow

User InteractionRequired

ScopeChanged

Impact

ConfidentialityLow

IntegrityLow

AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

Exploit Intelligence

48.05%probability of exploitation in 30 days

99thpercentile

Very high risk: more likely to be exploited than 99% of all known CVEs.

Known Exploited Vulnerability (CISA KEV)

OpenPLC ScadaBR Cross-site Scripting Vulnerability

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

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

Remediation due: 2025-12-19

References

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-12-01.