CVE-2025-66500
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 stored cross-site scripting (XSS) vulnerability exists in webplugins.foxit.com. A postMessage handler fails to validate the message origin and directly assigns externalPath to a script source, allowing an attacker to execute arbitrary JavaScript when a crafted postMessage is received.
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 confidenceA stored XSS vulnerability in webplugins.foxit.com where a postMessage handler fails to validate the message origin and directly assigns the externalPath parameter to a script source, allowing arbitrary JavaScript execution via crafted postMessage messages.
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< 2025-12-01CVSS 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
- Low
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/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 Foxit Pdf Editor Cloud installationCheck installed programs or application folder for Foxit Pdf Editor Cloud and note the version or installation dateAffected if Foxit Pdf Editor Cloud version predates 2025-12-01 or installation date is before December 2025
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Verify webplugin connectivityMonitor network traffic or check browser developer tools for any requests to webplugins.foxit.com domain when using the applicationAffected if The application connects to webplugins.foxit.com and uses the vulnerable postMessage handler
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Check browser console for postMessage trafficOpen browser developer tools (Console or Network tab) and look for postMessage communication targeting webplugins.foxit.com with externalPath parametersAffected if postMessage calls with externalPath parameter are observed being sent to the webplugins.foxit.com origin without referrer origin validation
The environment is affected if Foxit Pdf Editor Cloud version is earlier than the December 2025 release AND the application makes network calls to or interacts with webplugins.foxit.com services.
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 · scoped2025-12-01
Implement strict origin validation for all postMessage handlers and sanitize or whitelist the externalPath parameter before using it in script src attributes.
Pdf Editor Cloud version 2025-12-01 or later
- Upgrade Pdf Editor Cloud to version 2025-12-01 or later to resolve the stored XSS vulnerability in webplugins.foxit.com
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation4.0 h
- Testing4.0 h
- Review / QA3.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-66500 — 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-2025-66500 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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