CVE-2020-10893 in PhantomPDF
Summary
by MITRE
This vulnerability allows remote attackers to execute arbitrary code on affected installations of Foxit PhantomPDF 9.7.1.29511. 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 U3D objects embedded in a PDF. The issue results from the lack of proper validation of user-supplied data, which can result in a write past the end of an allocated structure. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-10189.
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Analysis
by VulDB Data Team • 05/07/2026
This vulnerability represents a critical heap-based buffer overflow in Foxit PhantomPDF version 9.7.1.29511 that enables remote code execution through maliciously crafted PDF files containing U3D objects. The flaw resides in the PDF parser's insufficient validation of user-supplied data during the processing of Universal 3D (U3D) embedded content, which is a 3D graphics format supported by PDF documents. The vulnerability specifically manifests when the application attempts to handle malformed U3D objects that exceed the allocated memory boundaries, creating a condition where memory corruption occurs beyond the intended buffer limits. This type of vulnerability falls under CWE-121, heap-based buffer overflow, and aligns with the ATT&CK technique T1203 for exploitation of software vulnerabilities. The attack requires user interaction through either visiting a malicious webpage hosting a compromised PDF or opening a malicious file directly, making it a classic example of a client-side exploitation vector.
The technical implementation of this vulnerability involves the improper memory management during U3D object parsing where the application fails to validate the size parameters of the embedded 3D content before allocating memory for processing. When a U3D object is parsed, the software calculates the required buffer size based on user-provided data without adequate bounds checking, leading to a situation where a crafted payload can cause a memory write operation that extends beyond the allocated buffer boundaries. This memory corruption can overwrite adjacent memory locations including function pointers, return addresses, or other critical program data structures, potentially allowing an attacker to redirect execution flow and execute arbitrary code within the context of the PhantomPDF process. The vulnerability essentially creates an opportunity for attackers to perform code injection attacks that can escalate privileges to the level of the current user.
The operational impact of this vulnerability extends beyond simple remote code execution, as it can be leveraged in sophisticated attack chains that may include privilege escalation, persistent backdoor installation, or data exfiltration. Since the exploitation requires user interaction, attackers typically employ social engineering techniques such as phishing campaigns or compromised websites to deliver malicious PDF files that contain the crafted U3D objects. The vulnerability affects the full range of PhantomPDF functionality, including web browser integration, desktop applications, and mobile platforms where the software is deployed. Organizations using this version of Foxit PhantomPDF are particularly vulnerable because the software processes PDF files automatically when opened, making it an attractive target for cybercriminals. The security implications include potential data breaches, system compromise, and unauthorized access to sensitive information stored in PDF documents.
Mitigation strategies for this vulnerability should include immediate patching of affected Foxit PhantomPDF installations to version 9.7.1.30327 or later, which contains the necessary fixes for the U3D object parsing logic. Network administrators should implement content filtering solutions that can detect and block PDF files containing suspicious U3D objects or malformed embedded content. Additional defensive measures include deploying sandboxing technologies to isolate PDF processing environments, implementing strict email filtering policies to prevent delivery of malicious PDF attachments, and conducting regular security awareness training for users to recognize social engineering attempts. Organizations should also consider disabling U3D object support entirely within their PDF processing workflows when possible, as this eliminates the attack surface associated with this specific vulnerability. The remediation approach aligns with the principle of defense in depth as outlined in NIST SP 800-53, requiring multiple layers of security controls to protect against various attack vectors.