CVE-2020-8856
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 atackers to execute arbitrary code on affected installations of Foxit PhantomPDF 9.6.0.25608. 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 watermarks. 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-9640.
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 · moderate confidenceA use-after-free or null pointer dereference vulnerability in Foxit PhantomPDF 9.6.0.25608 allows remote attackers to execute arbitrary code via a malicious PDF file or webpage. The flaw exists in the watermark handling functionality 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 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<= 9.7.0.29478<= 9.7.0.29455CVSS 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 Windows Control Panel, go to Programs and Features, or use PowerShell: Get-ItemProperty 'HKLM:\Software\Microsoft\Windows\CurrentVersion\Uninstall\*' | Where-Object {$_.DisplayName -like '*Foxit*'} | Select-Object DisplayName, DisplayVersionAffected if Either Foxit Reader or Foxit PhantomPDF is listed in installed programs
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Determine exact version numberIf the product is installed, right-click the Foxit icon, select Help, then About to view the exact versionBuild number displayedAffected if The displayed version falls within the affected ranges
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Compare Reader version to affected rangeIf Foxit Reader is installed, compare the installed versionBuild number to 9.7.0.29478 (all versions at or below this are affected)Affected if Reader version is 9.7.0.29478 or lower
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Compare PhantomPDF version to affected rangeIf Foxit PhantomPDF is installed, compare the installed versionBuild number to 9.7.0.29455 (all versions at or below this are affected)Affected if PhantomPDF version is 9.7.0.29455 or lower
You are affected if Foxit Reader version 9.7.0.29478 or lower, or Foxit PhantomPDF version 9.7.0.29455 or lower, is installed on your system.
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 PhantomPDF to the latest version provided by the vendor. Avoid opening untrusted PDF files or visiting untrusted websites until the patch is applied.
- Consultation2.0 h
- Implementation3.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,272.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-8856 — 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-2020-8856 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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