CVE-2021-34844
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-14033.
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 vulnerability in Foxit PDF Reader 11.0.0.49893 allows remote attackers to execute arbitrary code via malicious PDF files. The flaw exists in the Annotation object handling where the code fails to validate object existence before performing operations on it, leading to memory corruption that can be leveraged for code execution in the current process context.
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 productOpen Foxit PDF Reader or PDF Editor, go to Help > About to see the exact version number. Alternatively, check Programs and Features in Control Panel or the application's executable properties.Affected if The installed product is Foxit PDF Reader or Foxit PDF Editor with a version matching the affected ranges (<= 11.0.0.49893 for Reader; <= 10.1.4.37651 or = 11.0.0.49893 for Editor).
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Verify application version against affected rangesCompare the identified version number to the affected versions: Foxit PDF Reader <= 11.0.0.49893 or Foxit PDF Editor <= 10.1.4.37651 or = 11.0.0.49893.Affected if The installed version falls within or below these version numbers.
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Check JavaScript execution settingIn Foxit PDF Reader/Editor, go to Edit > Preferences > JavaScript. Verify whether JavaScript is enabled or disabled in the application settings.Affected if JavaScript execution is enabled, which increases the attack surface when processing untrusted PDF files.
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Review usage patterns for handling PDF filesAssess whether the user or organization commonly opens PDF files from untrusted or unknown sources, which is the required attack vector for this vulnerability.Affected if Users routinely open PDF files from untrusted or external sources without prior verification.
A user is affected if they have Foxit PDF Reader <= 11.0.0.49893 or Foxit PDF Editor <= 10.1.4.37651 (or = 11.0.0.49893) installed and process PDF files from potentially untrusted sources.
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 PDF Reader to the vendor-provided patched version. Until patched, avoid opening PDF files from untrusted sources and disable JavaScript execution in the PDF reader settings.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2021-34844 — 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-2021-34844 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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