OpenPLC ScadaBR Cross-site Scripting Vulnerability
n/a — n/a
OpenPLC ScadaBR through 0.9.1 on Linux and through 1.12.4 on Windows allows stored XSS via system_settings.shtm.
5.4
48.0%
Vector breakdown
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
- Published
- Jun 11, 2021
- Modified
- Dec 2, 2025
- Added to KEV
- Nov 28, 2025
- Federal patch due
- Dec 19, 2025
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.
Weakness classification
Proof-of-concept & exploitation references
Weaponization
Public repositories whose name or description references CVE-2021-26829, found via a live GitHub search at request time. These are community-sourced signals, not a verified working exploit — cross-check each one before relying on it, and treat higher star counts and recent activity as (weak) corroboration, not proof.
No public GitHub repositories referencing CVE-2021-26829 were found at last check. Absence here is not proof no exploit exists — see the references below for vendor advisories and write-ups.
References
How this class of flaw gets exploited
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 base score of 5.4 out of 10 (CVSS 3.1).
Is CVE-2021-26829 actively exploited in the wild?
Yes. CVE-2021-26829 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added Nov 28, 2025, meaning CISA has confirmed evidence of active exploitation.
What is the EPSS score for CVE-2021-26829?
48.0% - meaning FIRST.org's EPSS model estimates a 48.0% probability this vulnerability will be exploited in the wild within 30 days (99% percentile among all scored CVEs).
What type of vulnerability is CVE-2021-26829?
CVE-2021-26829 is classified under CWE-79 (CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')).
Cross-checked against
Impactr finds and proves whether CVE-2021-26829 — or flaws like it — are actually reachable in your own web apps and APIs, with a reproducible exploit as evidence.