CVE-2021-26829
OpenPLC ScadaBR Cross-site Scripting Vulnerability
- Medium 5.4
- Exploited: added to CISA KEV 28 Nov 2025
Description
OpenPLC ScadaBR through 0.9.1 on Linux and through 1.12.4 on Windows allows stored XSS via system_settings.shtm.
Key facts
- Published
- 11 Jun 2021
- Last changed
- 2 Dec 2025
- Assigned by
- mitre
- KEV added
- 28 Nov 2025
- KEV fix due
- 19 Dec 2025
- EPSS
- 48.05% likely to be exploited in the next 30 days, higher than 98.877% of CVEs (scores for 15 Nov 2026)
- SSVC (CISA)
- Exploitation: active; Automatable: no; Technical impact: partial
Severity scores
Each score is shown as its source gave it. They are not averaged or merged.
- 5.4CVSS 3.1, Mediumfrom CISA (ADP container)
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
What to do
- Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.CISA KEV required action
Historical context and remediation
This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.
No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.
Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.
Affected products
| Vendor | Product | Versions |
|---|---|---|
| n/a | n/a |
|
Timeline
- 11 Jun 2021 Published
- 28 Nov 2025 CVE-2021-26829 added to CISA KEV
- 28 Nov 2025 Added to the CISA KEV catalogue
Weakness
Practice this bug class
HackZoneLabs has a hands-on lab on XSS (stored, reflected, DOM) (CWE-79).