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MaxboardApplication · Maxb

CVE-2021-26634

CRITICAL · 9.8 CVSS v3.1 Published 2022-06-02
Fix available
A fix is available. Upgrade to 1.9.6 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

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 · unedited
SQL injection and file upload attacks are possible due to insufficient validation of input values in some parameters and variables of files compromising Maxboard, which may lead to arbitrary code execution or privilege escalation. Attackers can use these vulnerabilities to perform attacks such as stealing server management rights using a web shell.

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 confidence

Maxboard versions affected contain SQL injection vulnerabilities due to insufficient input validation in certain parameters, allowing attackers to inject malicious SQL queries. Additionally, inadequate file upload validation permits uploading of arbitrary files including web shells, enabling remote code execution and privilege escalation to server management rights.

MitigationImplement strict input validation and use parameterized queries/prepared statements for all database operations. For file uploads, implement whitelist-based file type validation, sanitize filenames, store uploads outside web root, and disable script execution in upload directories.

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
MaxboardApplication
Affected:< 1.9.6

CVSS 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
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/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 checks

Work through these to decide whether this CVE applies to you.

  1. Identify Maxboard installation version
    Check the version file or admin panel of the Maxboard installation. Common locations include a version.php file in the application root, or the admin dashboard 'About' or 'System Info' section.
    Affected if The installed version is unknown, missing, or cannot be verified as 1.9.6 or higher.
  2. Compare version to affected range
    Document the identified version number and compare it against the affected range: versions prior to 1.9.6 are vulnerable.
    Affected if The installed version is lower than 1.9.6 (for example, 1.9.5, 1.9.0, 1.8.x, etc.).
  3. Verify web application accessibility
    Confirm the Maxboard web interface is accessible via HTTP/HTTPS. Attempt to access the login or public-facing pages.
    Affected if The application is live and reachable - this is a prerequisite for the SQL injection and file upload vulnerabilities to be exploitable.
  4. Check for file upload functionality
    Locate the file upload feature in Maxboard (typically in admin panels, posting interfaces, or attachment handlers). Attempt to identify where file uploads are processed.
    Affected if File upload functionality is present and accessible to users - this module is subject to the arbitrary file upload vulnerability.

A user is affected if Maxboard version 1.9.6 or higher is not installed and the web application is accessible, as both the SQL injection and inadequate file upload validation flaws exist in vulnerable versions.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Upgrade available Upgrade to 1.9.6 or later
Fixed in 1.9.6
Interim mitigation

Implement strict input validation and use parameterized queries/prepared statements for all database operations. For file uploads, implement whitelist-based file type validation, sanitize filenames, store uploads outside web root, and disable script execution in upload directories.

Recommended fix Moderate confidence

Maxboard 1.9.6

  1. 1. Back up the existing Maxboard installation and its database before proceeding with any upgrade.
  2. 2. Download Maxboard version 1.9.6 or later from the official project repository or distribution source.
  3. 3. Review the official upgrade documentation specific to your current version for migration instructions.
  4. 4. Deploy the new version 1.9.6 files, overwriting the existing installation while preserving configuration files.
  5. 5. Run any database migration scripts if provided in the upgrade package.
  6. 6. Verify the upgrade was successful by checking the version number in the admin interface.
  7. 7. Test that SQL injection vectors are no longer exploitable and file upload functionality works correctly with proper validation.

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Maxboard Scoped from the published advisory
  • Consultation4.0 h
  • Implementation12.0 h
  • Testing6.0 h
  • Review / QA3.0 h
25.0 hours of engineering $4,400
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $7,040.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-26634 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • 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
  • No spam, self-promotion, credentials, or personal data