CVEs / CVE-2021-26829
CVE-2021-26829: OpenPLC ScadaBR Cross-site Scripting Vulnerability
- Known exploited in the CISA KEV catalog since 28 Nov 2025
- medium 5.4 CVSS 3.1 (NVD)
- EPSS 48% chance of exploitation in the next 30 days, higher than 98% of CVEs (30 Oct 2026)
- Last changed at its sources
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Summary
OpenPLC ScadaBR contains a cross-site scripting vulnerability via system_settings.shtm.
Description
OpenPLC ScadaBR through 0.9.1 on Linux and through 1.12.4 on Windows allows stored XSS via system_settings.shtm.
Affected and fixed versions
| Product | Affected | Fixed in |
|---|---|---|
| n/a n/a | n/a | — |
Exploitation
| In CISA KEV since | 28 Nov 2025 |
|---|---|
| Due date for US federal agencies | 19 Dec 2025 |
| Used in ransomware campaigns | Unknown |
| 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. |
Severity
| CVSS 3.1 | 5.4 mediumCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:NScored by NVD |
|---|---|
| Weakness | CWE-79 |
References
- CVE-2021-26829 on NVD
- CVE-2021-26829 in the CISA KEV catalog
- https://github.com/SCADA-LTS/Scada-LTS/pull/3211 (cited by CISA)
- http://forum.scadabr.com.br/t/report-falhas-de-seguranca-em-versoes-do-scadabr/3615/4 Vendor Advisory
- https://youtu.be/Xh6LPCiLMa8 Exploit, Third Party Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26829 US Government Resource
- https://www.forescout.com/blog/anatomy-of-a-hacktivist-attack-russian-aligned-group-targets-otics/ Third Party Advisory
Sources
Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.
This product uses data from the NVD API but is not endorsed or certified by the NVD.