CVE-2021-26829

OpenPLC ScadaBR: Cross-site Scripting

As of , CVE-2021-26829 in OpenPLC ScadaBR is on CISA's list of exploited vulnerabilities: CISA listed it on . Our patch-first group: Patch soon.

Exploited
Yes: CISA listed it on 28 November 2025
US federal deadline
19 December 202521 days after CISA listed it. US federal civilian agencies must fix it by then.
Used in ransomware campaigns
Not known to CISA
EPSS score
0.48Higher than 98% of the CVEs EPSS scores. EPSS estimates the chance of exploitation activity in the next 30 days.
Public exploit
None foundNeither Metasploit nor Exploit-DB lists one.
Fix
Vendor advice: github.comLinks below, from CISA's entry.

What CISA says to do

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

CISA's required action

  • github.comThis vulnerability could affect an open-source component, third-party library, protocol, or proprietary implementation that could be used…

What the flaw is

OpenPLC ScadaBR contains a cross-site scripting vulnerability via system_settings.shtm.

CISA's description

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

The CVE record's description, from mitre

CVE published
11 June 2021
Assigned by
mitre
CVSS
5.4 Medium (CVSS 3.1, from CISA-ADP)
CWE-79
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CISA SSVC, exploitation
active
CISA SSVC, automatable
no
CISA SSVC, technical impact
partial

Timeline

  1. The CVE record was published.
  2. CISA added it to its list of exploited vulnerabilities.
  3. The US federal deadline to fix it.

ScadaBR: other exploited entries

VulnerabilityProductOur groupListedDeadlineEPSS
CVE-2021-26828Unrestricted Upload of File with Dangerous TypeOpenPLC ScadaBRPatch soon0.39

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