CVE-2021-26829
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedOpenPLC ScadaBR through 0.9.1 on Linux and through 1.12.4 on Windows allows stored XSS via system_settings.shtm.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceOpenPLC ScadaBR contains a stored Cross-Site Scripting (XSS) vulnerability in the system_settings.shtm page. Attackers can inject malicious JavaScript payloads that persist on the server and execute in the browsers of users who access the affected settings page.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data<= 0.9.1<= 1.12.4CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- Low
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Confirm ScadaBR installationIdentify if ScadaBR web application is running by accessing the application's login page or checking for ScadaBR-specific files in the web server directory.Affected if ScadaBR is not installed or the web application is not present.
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Determine ScadaBR versionCheck the installed ScadaBR version by reviewing the application documentation, checking version files within the deployment directory, or accessing the About/Help section within the application interface.Affected if The installed version is 0.9.1 or lower, or 1.12.4 or lower.
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Verify system_settings.shtm accessibilityAttempt to access the system_settings.shtm page through the web interface by navigating to the system settings configuration area or directly requesting the endpoint if known.Affected if The page is accessible without authentication or accessible to low-privilege users.
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Inspect stored settings for malicious contentExamine the application's database or configuration files where system settings are stored, looking for any unexpected script tags, JavaScript event handlers, or encoded payloads that may have been injected into settings fields.Affected if Any JavaScript code or HTML tags are found stored in system settings fields that are rendered without proper encoding.
You are affected if ScadaBR versions 0.9.1 or lower or 1.12.4 or lower are installed and the system_settings.shtm page is accessible with stored user-supplied data rendered without output encoding.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataImplement proper input validation and output encoding on all user-controllable fields in system_settings.shtm. Apply context-appropriate escaping when rendering user-supplied data back to the browser.
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,408.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-26829 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-26829 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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