CVE-2021-41567
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 · uneditedThe new add subject parameter of Tad Uploader view book list function fails to filter special characters. Unauthenticated attackers can remotely inject JavaScript syntax and execute stored XSS attacks.
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 confidenceStored XSS vulnerability in Tad Uploader plugin's 'add subject' parameter within the view book list function. The parameter fails to sanitize special characters, allowing unauthenticated attackers to inject malicious JavaScript that executes when users view the affected content.
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< 3.5.4CVSS 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
- None
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/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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Verify Tad Uploader plugin is installedLocate the Tad Uploader plugin files in your CMS (typically in /wp-content/plugins/ or equivalent), or check the installed plugins list in your admin panel for 'Tad Uploader'Affected if The plugin is present in the system
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Check installed version numberView the plugin version in your CMS admin panel (plugin details page) or inspect the main plugin file header for 'Version: x.x.x'Affected if The version is below 3.5.4 (e.g., 3.5.3, 3.5.2, etc.)
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Confirm view book list function is accessibleIdentify if there is a public-facing page, shortcode, or endpoint that exposes the 'view book list' functionality (common paths include /book-list/ or similar URL patterns)Affected if The view book list page or endpoint exists and is publicly or internally accessible
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Verify add subject parameter is presentAccess the book list view and locate the 'add subject' input field within the form or functionality, or inspect page source for input name containing 'subject'Affected if The add subject input field exists and accepts user input without immediate validation feedback
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Test for XSS vulnerability in add subject parameterSubmit a test payload with special characters (e.g., <script>alert(1)</script> or similar) in the add subject field, then view the book list page to observe if the payload is rendered as raw HTML or executedAffected if The submitted payload is rendered unescaped in the page output or JavaScript executes when viewing the content
A user is affected if Tad Uploader plugin version is below 3.5.4 AND the view book list function with the add subject parameter is accessible and renders user input without sanitization.
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 · scoped3.5.4
Implement proper input validation and output encoding on the 'add subject' parameter to filter or escape HTML/script characters before storing and rendering the data.
Tad Uploader 3.5.4 or later
- Identify the current installed version of Tad Uploader in your system
- Download Tad Uploader version 3.5.4 or later from the official source (www.twcert.org.tw or vendor repository)
- Backup your current installation and database before proceeding with the upgrade
- Apply the upgrade following the standard plugin/module upgrade procedure for your platform
- Verify that the upgrade was successful by checking the installed version
- Test the 'view book list' function to confirm the XSS vulnerability is remediated
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-41567 — 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-2021-41567 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
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