Stored XSS in OpenPLC ScadaBR system_settings.shtm
CVE-2021-26829 is a stored cross-site scripting vulnerability in OpenPLC ScadaBR affecting versions through 0.9.1 on Linux and through 1.12.4 on Windows. The flaw is exposed via the system_settings.shtm page/component, where attacker-controlled input can be stored and later rendered in a victim’s browser without proper neutralization. The provided content indicates the issue was patched in June 2021 and has been added to CISA’s Known Exploited Vulnerabilities catalog based on evidence of active exploitation. Reporting cited in the content shows the vulnerability was used to inject HTML/JavaScript into HMI content, including the login page description, causing attacker-supplied script to execute when the page was viewed.
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Impact, mitigation & remediation
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Impact
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Mitigation
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Remediation
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Exploits
No public exploits tracked yet. Mallory keeps watching.
No public exploit code observed for this vulnerability.
Affected products & vendors
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Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
Recent activity
58 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
Cross-site scripting (XSS) vulnerability in OpenPLC ScadaBR (Windows and Linux versions) added to KEV due to active exploitation.
A cross-site scripting vulnerability in OpenPLC ScadaBR, actively exploited in November 2025.
A vulnerability in ScadaBR, an open-source SCADA system, which has been confirmed as exploited in the wild and is now included in CISA's Known Exploited Vulnerabilities catalog.
A cross-site scripting (XSS) vulnerability in OpenPLC ScadaBR affecting the system_settings.shtm functionality on Windows and Linux.
The version that knows your environment.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.