CVE-2018-20312
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, a different issue than CVE-2018-20310 because of a different opcode.
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 vulnerability exists in the proxyDoAction function of Foxit Reader before version 9.5 and PhantomPDF before 8.3.10/9.x before 9.5. This race condition can be exploited to trigger either a stack-based buffer overflow or an out-of-bounds read, potentially allowing remote code execution or information disclosure. The issue is distinct from CVE-2018-20310 due to a different opcode being involved.
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 softwareOpen Windows Control Panel, go to Programs and Features, or use PowerShell command: Get-ItemProperty 'HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\*' | Where-Object {$_.DisplayName -like '*Foxit*'} | Select-Object DisplayName, DisplayVersionAffected if Neither Foxit Reader nor PhantomPDF is installed (not affected)
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Determine Foxit Reader versionIf installed, right-click the Foxit Reader shortcut, select Properties, and check the version field, or open Foxit Reader and go to Help > About Foxit Reader to view the exact version numberAffected if Version is below 9.5
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Determine PhantomPDF versionIf PhantomPDF is installed, open it and go to Help > About PhantomPDF, or check the version in Programs and Features, noting whether it is version 8.x or 9.xAffected if Version is below 8.3.10, or is 9.x but below 9.5
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Check for vulnerable feature usageReview PDF documents opened in Foxit for the presence of proxy actions in forms, which triggers the proxyDoAction function. This is typically found in PDF forms with JavaScript actions or interactive form elementsAffected if PDFs with proxy actions are being processed while the version is in the affected range
User is affected if Foxit Reader below 9.5 or PhantomPDF below 8.3.10/9.5 is installed AND the software is used to process PDF documents containing proxy actions that invoke the vulnerable proxyDoAction function.
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 8.3.10/9.5 or later to address this vulnerability. Prioritize deployment given the high CVSS score and potential for code execution.
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2018-20312 — 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-2018-20312 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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