CVE-2021-26636
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 · uneditedStored XSS and SQL injection vulnerability in MaxBoard could lead to occur Remote Code Execution, which could lead to information exposure and privilege escalation.
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 · moderate confidenceMaxBoard contains a stored cross-site scripting (XSS) vulnerability and a SQL injection vulnerability. The stored XSS allows attackers to inject malicious scripts that are persisted on the server and executed when other users view the affected content. The SQL injection flaw enables attackers to manipulate database queries, which can be escalated to achieve remote code execution, expose sensitive information, and elevate privileges within the system.
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< 1.9.6.1CVSS 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
- None
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H
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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Identify MaxBoard installation and versionLocate the MaxBoard application directory or check the application's version information file. Common methods include checking the 'about' page in the admin panel, examining the application's main configuration file, or running a package manager query if installed via package management.Affected if The installed version is lower than 1.9.6.1 or the version cannot be determined but MaxBoard is present.
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Confirm web interface accessibilityVerify that the MaxBoard web interface is accessible to users or attackers. Attempt to access the login page, registration page, or any public-facing endpoints.Affected if The web interface is accessible over HTTP/HTTPS and the application version is below 1.9.6.1.
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Identify user input points in the applicationExamine the application for features that accept and store user-supplied data such as message boards, user profiles, comments, or forum posts. These are potential injection points for both XSS and SQL injection.Affected if User input fields are present and the application version is below 1.9.6.1.
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Inspect stored content for malicious scriptsReview the application's database or stored content for any suspicious script tags, HTML elements, or encoded payloads that could represent injected XSS code. Check tables that store user-generated content.Affected if Unexpected script tags or HTML elements are found in stored content, indicating a potential XSS attack has occurred.
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Check database query handlingReview application source code or database logs for evidence of SQL queries constructed using string concatenation instead of parameterized queries. Look for direct user input being included in SQL statements.Affected if Database queries appear to incorporate user input without proper parameterization, making SQL injection possible.
The environment is affected if MaxBoard (Maxb Maxboard) version 1.9.6.1 or higher is not installed, and the web interface with user input functionality is accessible.
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.
dbcve · scoped1.9.6.1
Implement strict input validation and output encoding for all user-supplied data to prevent stored XSS attacks. Use parameterized queries or prepared statements for all database operations to eliminate SQL injection vectors. After fixing the SQL injection, verify that remote code execution is no longer achievable through database compromise.
MaxBoard 1.9.6.1 or later
- 1. Backup the entire MaxBoard installation directory and database before making any changes.
- 2. Download MaxBoard version 1.9.6.1 or the latest stable version from the official source.
- 3. Replace the existing MaxBoard files with the new version files, preserving any custom configurations if applicable.
- 4. Verify that custom themes or plugins are compatible with the new version.
- 5. Test the application functionality to ensure the upgrade did not break existing features.
- 6. Verify the fix by confirming that the XSS and SQL injection vulnerabilities are no longer exploitable.
- 7. Monitor logs for any unusual activity following the upgrade.
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation8.0 h
- Implementation16.0 h
- Testing8.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-26636 — 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-2021-26636 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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