CVE-2021-34831
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 affected installations of Foxit Reader 10.1.4.37651. 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 Document objects. The issue results from the lack of validating 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-13741.
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 confidenceFoxit Reader 10.1.4.37651 contains a use-after-free or null pointer dereference vulnerability in its Document object handling. The software fails to validate object existence before performing operations, allowing remote attackers to achieve arbitrary code execution in the current process context via malicious PDF files or webpages.
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<= 11.0.0.49893<= 10.1.4.37651= 11.0.0.49893CVSS 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
- Local
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/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 installed programs for 'Foxit Reader' or 'Foxit PDF Editor' in Control Panel > Programs and Features, or check the application executable propertiesAffected if The system has either Foxit Reader or Foxit PDF Editor installed
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Determine Foxit Reader versionOpen Foxit Reader, go to Help > About Foxit Reader, or right-click the executable and select Properties > Details to view the version numberAffected if Version is 11.0.0.49893 or lower (any version <= 11.0.0.49893)
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Determine Foxit PDF Editor versionOpen Foxit PDF Editor, go to Help > About Foxit PDF Editor, or right-click the executable and select Properties > Details to view the version numberAffected if Version is 10.1.4.37651 or lower, or exactly version 11.0.0.49893
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Verify vulnerable feature exposureConfirm the application is configured to open PDF files or render web content. The vulnerability triggers when processing malicious PDF documents or webpage content within the applicationAffected if The application can open PDF files or display embedded web content, which is the default behavior for both Reader and Editor
A system is affected if it runs Foxit Reader <= 11.0.0.49893 or Foxit PDF Editor <= 10.1.4.37651 or = 11.0.0.49893, and the user opens untrusted PDF files or visits malicious webpages that trigger the Document object handling flaw.
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 dataUpdate Foxit Reader to the vendor's latest patched version. Avoid opening untrusted PDF files or visiting untrusted webpages until the update is applied.
- Consultation1.0 h
- Testing1.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2021-34831 — 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-2021-34831 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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