CVE-2018-17631
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 · uneditedThis vulnerability allows remote attackers to execute arbitrary code on vulnerable installations of Foxit Reader 9.2.0.9297. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file. The specific flaw exists within the handling of the removeInstance event. The issue results from the lack of validation of the existence of an object prior to performing operations on the object. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-6500.
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 confidenceUse-after-free or null pointer dereference in Foxit Reader 9.2.0.9297's JavaScript event handling for the removeInstance event. The lack of validation of object existence prior to operations allows remote code execution when a user opens a malicious PDF or visits a malicious webpage.
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<= 9.2.0.9297<= 9.2.0.9297CVSS 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
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/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 productCheck Programs and Features or use command: reg query 'HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\{GUID}' /v DisplayName to find Foxit Reader or Foxit PhantomPDFAffected if Either Foxit Reader or Foxit PhantomPDF is installed
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Check Foxit version numberIn Foxit Reader/PhantomPDF, go to Help > About or right-click the application in taskbar and select About. Note the full version number displayed.Affected if Version is 9.2.0.9297 or lower (any version up to and including 9.2.0.9297)
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Verify JavaScript is enabledIn Foxit Reader/PhantomPDF, go to Edit > Preferences > JavaScript. Check if 'Enable Adobe JavaScript' is checked/enabled.Affected if JavaScript is enabled (the checkbox is ticked)
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Confirm removeInstance event usageThis requires analyzing PDF files for JavaScript using the removeInstance event handler. Open the PDF with Foxit's JavaScript Debugger (available in Edit > Preferences > JavaScript > Enable JavaScript Debugger) and check for code involving app.removeInstance or document.removeInstance.Affected if PDFs containing removeInstance JavaScript event handlers are opened
You are affected if Foxit Reader or PhantomPDF version 9.2.0.9297 or lower is installed AND JavaScript execution is enabled in the application settings.
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 dataApply vendor patch from Foxit; alternatively disable JavaScript execution in Foxit Reader settings to mitigate risk until update is applied.
- Consultation2.0 h
- Implementation1.0 h
- Testing3.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2018-17631 — 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-2018-17631 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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- Version or environment caveats, and links to real fixes
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