CVE-2021-34842
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 PDF Reader 11.0.0.49893. 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 Annotation 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-14024.
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 use-after-free or null pointer dereference vulnerability in Foxit PDF Reader 11.0.0.49893 allows remote attackers to execute arbitrary code via a maliciously crafted PDF file. The flaw exists in the Annotation object handling where the code fails to validate that an object exists before performing operations on it, leading to memory corruption and code execution in the context of the current process.
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 Foxit product and versionOpen Foxit PDF Reader or Editor, then go to Help > About Foxit [Reader/Editor] to view the exact version number displayed in the dialog. Alternatively, right-click the application in the Start menu or taskbar, select Properties, and check the Version field.Affected if The displayed version is 11.0.0.49893 or lower for Foxit Reader, or 10.1.4.37651 or lower (or exactly 11.0.0.49893) for Foxit PDF Editor.
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Verify affected version rangesCompare your installed version against these ranges: Foxit Reader <= 11.0.0.49893; Foxit Editor <= 10.1.4.37651 or = 11.0.0.49893. If your version matches any of these, the vulnerability is present.Affected if The installed version falls within any of the affected version ranges listed.
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Check JavaScript execution statusIn Foxit Reader/Editor, go to Edit > Preferences > JavaScript. Verify whether JavaScript is enabled or disabled.Affected if JavaScript is enabled, as malicious PDF files can leverage JavaScript to trigger the Annotation object vulnerability.
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Confirm vulnerability is in Annotation handlingThis is a passive check: the vulnerability specifically exists in Annotation object handling within the PDF rendering engine. There is no specific configuration to disable this component; it is intrinsic to how Foxit processes PDF annotations.Affected if The Foxit application processes PDF annotations (a standard PDF feature) - this is the case for any standard PDF workflow, meaning any vulnerable version is at risk when opening a malicious PDF.
A user is affected if their installed Foxit PDF Reader is version 11.0.0.49893 or lower, or their Foxit PDF Editor is version 10.1.4.37651 or lower or exactly 11.0.0.49893, and they open a maliciously crafted PDF file.
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 the vendor patch by updating Foxit PDF Reader to the latest version. Until patched, instruct users to avoid opening untrusted PDF files and disable JavaScript execution in the reader if possible.
- Consultation2.0 h
- Implementation1.0 h
- Testing2.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2021-34842 — 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-2021-34842 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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