CISA Warns of OpenPLC ScadaBR cross-site scripting vulnerability Exploited in Attacks

CISA added CVE-2021-26829—an XSS vulnerability in OpenPLC ScadaBR's system_settings.shtm—to its Known Exploited Vulnerabilities catalog after observing active exploitation; the flaw can execute arbitrary script in administrator/authenticated user browsers, risking session hijack, credential theft, and configuration tampering in SCADA/OT environments, and federal agencies must remediate by December 19, 2025 under BOD 22-01.