CVE-2021-27731
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 · uneditedAccellion FTA 9_12_432 and earlier is affected by stored XSS via a crafted POST request to a user endpoint. The fixed version is FTA_9_12_444 and later.
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 confidenceAccellion FTA versions 9_12_432 and earlier contain a stored XSS vulnerability. An attacker can inject malicious JavaScript via a crafted POST request to a user endpoint, which is then persisted and executed when other users access the affected functionality.
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<= 9_12_432CVSS 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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Confirm Accellion FTA installationLocate and identify the Accellion FTA application in your environment. Check for FTA web directories, typical installation paths on the server, or consult your asset inventory for Accellion FTA software.Affected if Accellion FTA software is present in the environment
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Determine installed FTA versionAccess the FTA admin interface or check version files on the server. Typically, the version is visible in the login page footer, admin dashboard, or via a /VERSION endpoint if available. Compare your version to 9_12_432.Affected if The installed version is 9_12_432 or any earlier version (e.g., 9_12_400, 9_11_x, etc.)
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Identify user-facing endpoints accepting POST requestsReview FTA web application endpoints that accept user input via POST method, particularly those that store and display content back to users. Common targets include file upload, message, or user profile endpoints.Affected if The FTA user interface with POST submission functionality is accessible and enabled
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Check for existing stored malicious contentInspect FTA database tables or user-generated content storage for suspicious script tags, JavaScript payloads, or encoded content in fields that accept user input. Query the backend database for stored XSS patterns if database access is available.Affected if Malicious JavaScript or script tags are found persisted in FTA user data fields
A system is affected if Accellion FTA version 9_12_432 or earlier is installed and the user endpoint functionality that accepts and stores POST requests is enabled and 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.
From vendor dataUpgrade Accellion FTA to version FTA_9_12_444 or later to patch the stored XSS vulnerability. Note that Accellion FTA was deprecated in 2021; organizations should evaluate migration to supported Accellion solutions or alternative secure file transfer platforms.
- Consultation6.0 h
- Implementation12.0 h
- Testing8.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $8,448.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-27731 — 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-2021-27731 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