# CVE-2021-26829: OpenPLC ScadaBR Cross-site Scripting Vulnerability

- Exploited (CISA KEV): yes, added 2025-11-28
- Published: 2021-06-11
- CVSS: 5.4 MEDIUM (v3.1)
- EPSS: 48.0% (99th percentile)
- CWE: CWE-79

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

## Edge WAF coverage (claimed by vendors, not measured)

| Vendor | Status | First rule | Days after publication |
|---|---|---|---|
| Cloudflare | Before feed history | — | — |
| AWS | No public claim | — | — |
| Microsoft Azure | No public claim | — | — |
| Google Cloud | Before feed history | — | — |
| Fastly | Before feed history | — | — |
| F5 | Before feed history | — | — |
| Akamai | No public source | — | — |
| OWASP CRS | Before feed history | — | — |

"No public claim" means no vendor statement names this CVE; "Before feed history" means the CVE is older than the vendor feed. In both cases generic rules may still block it.

HTML: https://cve.vigilbase.com/cve/CVE-2021-26829 · JSON: https://cve.vigilbase.com/api/v1/cves/CVE-2021-26829