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Known Exploited Vulnerability
5.4
MEDIUM CVSS 3.1
CVE-2021-26829
OpenPLC ScadaBR Cross-site Scripting Vulnerability - [Actively Exploited]
Description

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

INFO

Published Date :

June 11, 2021, 12:15 p.m.

Last Modified :

Dec. 1, 2025, 3:23 p.m.

Remotely Exploit :

Yes !

Source :

[email protected]
CISA Notification
CISA KEV (Known Exploited Vulnerabilities)

For the benefit of the cybersecurity community and network defenders—and to help every organization better manage vulnerabilities and keep pace with threat activity—CISA maintains the authoritative source of vulnerabilities that have been exploited in the wild.

Description :

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

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.

Notes :

This vulnerability could affect an open-source component, third-party library, protocol, or proprietary implementation that could be used by different products. For more information, please see: https://github.com/SCADA-LTS/Scada-LTS/pull/3211 ; https://nvd.nist.gov/vuln/detail/CVE-2021-26829

Affected Products

The following products are affected by CVE-2021-26829 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Linux linux_kernel
1 Microsoft windows
1 Scadabr scadabr
1 Openplcproject scadabr
: Total Affected Vendor : 4 | Products : 4
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 2.0 LOW [email protected]
CVSS 3.1 MEDIUM [email protected]
CVSS 3.1 MEDIUM 134c704f-9b21-4f2e-91b3-4a467353bcc0
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2021-26829.

URL Resource
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
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
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2021-26829 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2021-26829 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2021-26829 vulnerability anywhere in the article.

  • Daily CyberSecurity
CISA KEV Alert: WinRAR Zero-Day Used for Malware Injection and Windows UAF RCE Under Active Attack

The Cybersecurity and Infrastructure Security Agency (CISA) has issued a new mandate for federal agencies to patch their systems immediately, following evidence of active exploitation in the wild. The ... Read more

Published Date: Dec 10, 2025 (5 days, 16 hours ago)
  • security.nl
VS meldt misbruik van cross-site scripting-kwetsbaarheid in ScadaBR

Aanvallers maken misbruik van een cross-site scripting (XSS)-lek in ScadaBR, een open source Supervisory Control and Data Acquisition (SCADA) systeem. Dat meldt het Cybersecurity and Infrastructure Se ... Read more

Published Date: Dec 01, 2025 (2 weeks ago)
  • The Hacker News
CISA Adds Actively Exploited XSS Bug CVE-2021-26829 in OpenPLC ScadaBR to KEV

Nov 30, 2025Ravie LakshmananHacktivism / Vulnerability The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has updated its Known Exploited Vulnerabilities (KEV) catalog to include a sec ... Read more

Published Date: Nov 30, 2025 (2 weeks, 1 day ago)
  • CybersecurityNews
CISA Warns of OpenPLC ScadaBR cross-site scripting vulnerability Exploited in Attacks

The Cybersecurity and Infrastructure Security Agency (CISA) has officially updated its Known Exploited Vulnerabilities (KEV) catalog to include a critical flaw in OpenPLC ScadaBR, confirming that thre ... Read more

Published Date: Nov 29, 2025 (2 weeks, 2 days ago)
  • Daily CyberSecurity
Critical Alert: Apache Kvrocks ‘RESET’ Command Flaw Grants Admin Privileges

The Apache Software Foundation has issued a critical security advisory for Apache Kvrocks, a distributed key-value NoSQL database compatible with the Redis protocol. Two significant vulnerabilities ha ... Read more

Published Date: Nov 29, 2025 (2 weeks, 2 days ago)
  • Daily CyberSecurity
CISA Flags Actively Exploited OpenPLC Flaw (CVE-2021-26829)

The Cybersecurity and Infrastructure Security Agency (CISA) has issued a new mandate for federal agencies to secure their industrial control systems following evidence of active exploitation in the wi ... Read more

Published Date: Nov 29, 2025 (2 weeks, 2 days ago)
  • europa.eu
Cyber Brief 25-11 - October 2025

Cyber Brief (October 2025)November 3, 2025 - Version: 1TLP:CLEARExecutive summaryWe analysed 281 open source reports for this Cyber Brief1.Relating to cyber policy and law enforcement, the European Co ... Read more

Published Date: Nov 01, 2025 (1 month, 2 weeks ago)
  • CybersecurityNews
Pro-Russian Hacktivist Attacking OT/ICS Devices to Steal Login Credentials

A newly identified pro-Russian hacktivist group has successfully infiltrated operational technology and industrial control systems belonging to critical infrastructure organizations, employing sophist ... Read more

Published Date: Oct 14, 2025 (2 months ago)
  • Daily CyberSecurity
Pro-Russian Hacktivist Group TwoNet Exposed for Fabricating Critical Infrastructure Attacks to Boost Reputation

Forescout Research has uncovered a disturbing new tactic among pro-Russian hacktivists — fabricating real-world critical infrastructure attacks to inflate their reputation. In a recent case, a newly f ... Read more

Published Date: Oct 13, 2025 (2 months ago)
  • The Register
Pro-Russia hacktivist group dies of cringe after falling into researchers' trap

Security researchers say they duped pro-Russia cybercriminals into targeting a fake critical infrastructure organization, which the crew later claimed - via their Telegram group - to be a real-world a ... Read more

Published Date: Oct 10, 2025 (2 months ago)
  • BleepingComputer
Hacktivists target critical infrastructure, hit decoy plant

A pro-Russian hacktivist group called TwoNet pivoted in less than a year from launching distributed denial-of-service (DDoS) attacks to targeting critical infrastructure. Recently, the threat actor cl ... Read more

Published Date: Oct 09, 2025 (2 months ago)

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2021-26829 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • Modified Analysis by [email protected]

    Dec. 01, 2025

    Action Type Old Value New Value
    Added CPE Configuration AND OR *cpe:2.3:a:scadabr:scadabr:*:*:*:*:*:*:*:* versions up to (including) 0.9.1 OR cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*
    Added CPE Configuration AND OR *cpe:2.3:a:scadabr:scadabr:*:*:*:*:*:*:*:* versions up to (including) 1.12.4 OR cpe:2.3:o:microsoft:windows:-:*:*:*:*:*:*:*
    Removed CPE Configuration OR *cpe:2.3:a:openplcproject:scadabr:*:*:*:*:*:linux:*:* versions up to (including) 0.9.1 *cpe:2.3:a:openplcproject:scadabr:*:*:*:*:*:windows:*:* versions up to (including) 1.12.4
    Added Reference Type CISA-ADP: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26829 Types: US Government Resource
    Added Reference Type CISA-ADP: https://www.forescout.com/blog/anatomy-of-a-hacktivist-attack-russian-aligned-group-targets-otics/ Types: Third Party Advisory
  • CVE CISA KEV Update by 9119a7d8-5eab-497f-8521-727c672e3725

    Nov. 29, 2025

    Action Type Old Value New Value
    Added Date Added 2025-11-28
    Added Due Date 2025-12-19
    Added 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.
    Added Vulnerability Name OpenPLC ScadaBR Cross-site Scripting Vulnerability
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Nov. 28, 2025

    Action Type Old Value New Value
    Added CVSS V3.1 AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
    Added CWE CWE-79
    Added Reference https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-26829
    Added Reference https://www.forescout.com/blog/anatomy-of-a-hacktivist-attack-russian-aligned-group-targets-otics/
  • CVE Modified by af854a3a-2127-422b-91ae-364da2661108

    Nov. 21, 2024

    Action Type Old Value New Value
    Added Reference http://forum.scadabr.com.br/t/report-falhas-de-seguranca-em-versoes-do-scadabr/3615/4
    Added Reference https://youtu.be/Xh6LPCiLMa8
  • CVE Modified by [email protected]

    May. 14, 2024

    Action Type Old Value New Value
  • Initial Analysis by [email protected]

    Jun. 21, 2021

    Action Type Old Value New Value
    Added CVSS V2 Metadata Victim must voluntarily interact with attack mechanism
    Added CVSS V2 NIST (AV:N/AC:M/Au:S/C:N/I:P/A:N)
    Added CVSS V3.1 NIST AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
    Changed Reference Type http://forum.scadabr.com.br/t/report-falhas-de-seguranca-em-versoes-do-scadabr/3615/4 No Types Assigned http://forum.scadabr.com.br/t/report-falhas-de-seguranca-em-versoes-do-scadabr/3615/4 Vendor Advisory
    Changed Reference Type https://youtu.be/Xh6LPCiLMa8 No Types Assigned https://youtu.be/Xh6LPCiLMa8 Exploit, Third Party Advisory
    Added CWE NIST CWE-79
    Added CPE Configuration OR *cpe:2.3:a:openplcproject:scadabr:*:*:*:*:*:linux:*:* versions up to (including) 0.9.1 *cpe:2.3:a:openplcproject:scadabr:*:*:*:*:*:windows:*:* versions up to (including) 1.12.4
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
Vulnerability Scoring Details
Base CVSS Score: 5.4
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact
Base CVSS Score: 3.5
Access Vector
Access Complexity
Authentication
Confidentiality Impact
Integrity Impact
Availability Impact
Exploit Prediction

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.

35.40 }} 2.61%

score

0.96877

percentile