CVE-2018-19201
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 · uneditedA reflected XSS vulnerability in the ModCP Profile Editor in MyBB before 1.8.20 allows remote attackers to inject JavaScript via the 'username' parameter.
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 confidenceA reflected XSS vulnerability in the ModCP Profile Editor of MyBB before version 1.8.20 allows remote attackers to inject arbitrary JavaScript via the 'username' parameter. The vulnerability occurs because user-supplied input in the username field is not properly sanitized or encoded before being reflected in the response.
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< 1.8.20CVSS 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
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.0/AV:N/AC:L/PR:N/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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Identify installed MyBB versionLocate the version.php file in your MyBB installation directory (usually at /inc/version.php) or log into the MyBB admin control panel and check the version information typically displayed on the dashboard or in the system health sectionAffected if The version number shown is less than 1.8.20 (for example, 1.8.19, 1.8.18, or earlier)
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Verify ModCP module is accessibleCheck if the Moderator Control Panel (ModCP) is enabled in your MyBB installation. This can typically be found in the admin control panel under Configuration > Settings > ModCP Settings, or by attempting to access the /modcp/ URL path on your forumAffected if ModCP is enabled and accessible to moderator-level users on your forum
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Confirm username parameter handling in ModCP Profile EditorLog into ModCP and navigate to the Profile Editor section where usernames can be modified. Submit a test username containing a simple script tag such as <script>alert(1)</script> and observe whether the tag is reflected as-is in the response page without encodingAffected if The submitted username is reflected in the page output without proper HTML encoding (the script tag executes or appears literally in the page source)
You are affected if your installed MyBB version is below 1.8.20 AND the ModCP Profile Editor is accessible to users, which allows the unsanitized username parameter to reflect malicious JavaScript in the response.
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 data1.8.20
Upgrade MyBB to version 1.8.20 or later, which includes the patch for this vulnerability. If immediate upgrade is not possible, apply input validation and output encoding to the username parameter in the ModCP Profile Editor.
- Consultation2.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-19201 — 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-2018-19201 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
- No spam, self-promotion, credentials, or personal data