CVE-2018-20310
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 · uneditedFoxit Reader before 9.5, and PhantomPDF before 8.3.10 and 9.x before 9.5, has a proxyDoAction race condition that can cause a stack-based buffer overflow or an out-of-bounds read.
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 race condition in the proxyDoAction function of Foxit Reader (before 9.5) and PhantomPDF (before 8.3.10 and 9.x before 9.5) allows attackers to trigger a stack-based buffer overflow or out-of-bounds read. The race window occurs during concurrent access to shared resources, enabling memory corruption that can be exploited for code execution or information disclosure.
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< 8.3.10>= 9.0, < 9.5< 9.5CVSS 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
- High
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:H/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 checksWork through these to decide whether this CVE applies to you.
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Identify installed Foxit productOpen the application and go to Help > About, or check the Windows registry under HKLM\SOFTWARE\Foxit Software for the product nameAffected if The product is Foxit Reader or PhantomPDF
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Check Foxit Reader versionIn the application, go to Help > About and note the version number displayed (format typically 9.x.x)Affected if The version is lower than 9.5 (any 9.0-9.4.x release)
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Check PhantomPDF versionIn the application, go to Help > About and note the version number; check both 8.x and 9.x branchesAffected if The version is lower than 8.3.10 (8.x branch) or between 9.0 and 9.4.x (9.x branch)
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Verify JavaScript execution is enabledIn Foxit Reader/PhantomPDF, go to File > Preferences > JavaScript (or Edit > Preferences > JavaScript) and check if JavaScript is enabledAffected if JavaScript execution is enabled - this is required for the proxyDoAction function to be reachable
You are affected if you run Foxit Reader below version 9.5 or PhantomPDF below version 8.3.10 (or 9.x below 9.5) AND have JavaScript execution enabled in the application preferences.
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 data8.3.109.5
Upgrade Foxit Reader to version 9.5 or later, and PhantomPDF to version 8.3.10 or later (or 9.x to 9.5 or later). If upgrading is not immediately feasible, restrict user interaction with untrusted PDF files and disable JavaScript execution in the application settings.
- Consultation4.0 h
- Implementation16.0 h
- Testing12.0 h
- Review / QA6.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-20310 — 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-2018-20310 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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