CVE-2020-10903 in PhantomPDF
Summary
by MITRE
This vulnerability allows remote attackers to disclose sensitive information 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 read past the end of an allocated object. An attacker can leverage this in conjunction with other vulnerabilities to execute code in the context of the current process. Was ZDI-CAN-10463.
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Analysis
by VulDB Data Team • 05/07/2026
CVE-2020-10903 represents a critical information disclosure vulnerability affecting Foxit PhantomPDF version 9.7.1.29511 that demonstrates a classic buffer over-read condition within the Universal 3D object processing functionality. This vulnerability resides in the PDF parsing engine's handling of U3D objects which are embedded 3D models used within PDF documents to provide interactive three-dimensional content. The flaw manifests when the application processes malformed U3D objects without proper input validation, leading to memory access violations that can expose sensitive data from adjacent memory regions. This type of vulnerability falls under CWE-125, known as "Out-of-bounds Read", which is classified as a memory safety error that allows attackers to read data beyond the intended memory boundaries. The vulnerability requires user interaction to exploit, meaning a victim must visit a malicious webpage or open a specially crafted PDF file containing the malformed U3D object. This attack vector aligns with the ATT&CK technique T1203, "Exploitation for Client Execution", where adversaries leverage vulnerabilities in software applications to execute code on target systems.
The technical implementation of this vulnerability involves the PDF renderer's failure to properly validate the size and structure of U3D object data during parsing operations. When processing embedded 3D content, the application allocates memory buffers based on expected data sizes from the U3D object header information. However, due to inadequate validation checks, malformed data can cause the parser to read beyond the allocated buffer boundaries, potentially accessing memory containing stack canaries, return addresses, or other sensitive information. This memory corruption can result in information disclosure that may include cryptographic keys, session tokens, or other confidential data. The vulnerability's exploitation potential extends beyond simple information disclosure, as the read past the end of an allocated object condition can provide attackers with sufficient information to construct more sophisticated attacks such as return-oriented programming (ROP) chains or heap spraying techniques.
The operational impact of CVE-2020-10903 is significant for organizations using Foxit PhantomPDF as their primary PDF viewing solution, particularly in enterprise environments where PDF documents are frequently shared and opened. The vulnerability's requirement for user interaction makes it particularly dangerous in social engineering campaigns where attackers craft malicious PDF documents designed to exploit this weakness. Attackers can leverage this vulnerability as part of a multi-stage attack chain, using the information disclosure to gather system information that can then be combined with other exploits to achieve remote code execution. The vulnerability's classification as a ZDI-CAN-10463 indicates it was recognized by the Zero Day Initiative and received proper CVE assignment, highlighting its severity and potential impact across various threat actors. Organizations running affected versions of Foxit PhantomPDF should consider immediate remediation actions, as the vulnerability can be exploited remotely without requiring authentication or specialized privileges.
Mitigation strategies for this vulnerability should focus on immediate patch deployment from Foxit Corporation, as the vendor would have released a security update addressing the U3D object parsing logic. Organizations should also implement network-based controls such as PDF content filtering and sandboxing solutions that can detect and block malicious PDF files before they reach end users. Additionally, user education programs should emphasize the importance of avoiding suspicious PDF attachments and websites, particularly those that may contain embedded 3D content. Security teams should monitor for indicators of compromise related to PDF-based attacks and consider implementing application whitelisting policies that restrict execution of PDF readers from untrusted sources. The vulnerability serves as a reminder of the importance of input validation in multimedia content processing and highlights the need for robust memory safety practices in PDF rendering engines, particularly those handling complex embedded objects like 3D graphics.