How severe is CVE-2021-26829?

CVE-2021-26829 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2021-26829 being actively exploited?

Yes. CVE-2021-26829 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2025-11-28, which means active exploitation has been confirmed. It should be prioritised for remediation.

What products are affected by CVE-2021-26829?

CVE-2021-26829 affects Scadabr. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-26829?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.

Does CVE-2021-26829 have an EU (EUVD) identifier?

Yes. CVE-2021-26829 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-13614. It is also flagged as exploited in the EUVD (since 2025-11-28).

When was CVE-2021-26829 published?

CVE-2021-26829 was published on 2021-06-11 and last updated on 2026-06-17.

CVE-2021-26829

CVE-2021-26829 is a medium-severity vulnerability in Scadabr with a CVSS 3.x base score of 5.4. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2025-11-28). The underlying weakness is classified as CWE-79.

Key facts

Severity: Medium (CVSS 3.x base score 5.4)
CVSS v2: 3.5
EPSS exploit prediction: 48% (99th percentile)
Actively exploited: Yes — listed in CISA KEV (added 2025-11-28)
EU (EUVD) id: EUVD-2021-13614
EU exploitation: Flagged exploited in the ENISA EU Vulnerability Database (since 2025-11-28)
Weakness: CWE-79
Affected product: Scadabr
Published: 2021-06-11
Last modified: 2026-06-17

Description

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

Frequently asked questions

What is CVE-2021-26829?: OpenPLC ScadaBR through 0.9.1 on Linux and through 1.12.4 on Windows allows stored XSS via system_settings.shtm.
How severe is CVE-2021-26829?: CVE-2021-26829 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires low privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2021-26829 being actively exploited?: Yes. CVE-2021-26829 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2025-11-28, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2021-26829?: CVE-2021-26829 affects Scadabr. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-26829?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
Does CVE-2021-26829 have an EU (EUVD) identifier?: Yes. CVE-2021-26829 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-13614. It is also flagged as exploited in the EUVD (since 2025-11-28).
When was CVE-2021-26829 published?: CVE-2021-26829 was published on 2021-06-11 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:scadabr:scadabr:*:*:*:*:*:*:*:*

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