CVE-2023-40468 in PDF-XChange Editor
Summary
by MITRE • 05/03/2024
PDF-XChange Editor EMF File Parsing Out-Of-Bounds Read Information Disclosure Vulnerability. This vulnerability allows remote attackers to disclose sensitive information on affected installations of PDF-XChange Editor. 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 parsing of EMF files. Crafted data in an EMF file can trigger a read past the end of an allocated buffer. An attacker can leverage this in conjunction with other vulnerabilities to execute arbitrary code in the context of the current process. Was ZDI-CAN-20620.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 05/19/2025
This vulnerability resides in the PDF-XChange Editor software's handling of EMF (Enhanced Metafile) files, representing a critical out-of-bounds read condition that exposes sensitive information through memory access violations. The flaw manifests during the parsing process of EMF files where crafted malicious data can cause the application to read memory locations beyond the allocated buffer boundaries. This type of vulnerability falls under CWE-125, which specifically addresses out-of-bounds read conditions that can lead to information disclosure and potentially more severe exploitation vectors. The vulnerability requires user interaction to be exploited, meaning an attacker must convince a target to open a malicious EMF file or visit a compromised webpage that triggers the vulnerable parsing code path.
The technical implementation of this vulnerability demonstrates how improper bounds checking in file format parsers can create dangerous memory access patterns. When an EMF file is processed, the application's buffer management fails to properly validate the size and structure of incoming data, allowing an attacker to manipulate the parsing logic into accessing memory regions that should remain protected. This creates a pathway for information disclosure where adjacent memory contents may be read and potentially exposed to unauthorized parties. The vulnerability's classification as an information disclosure issue means that while it may not directly enable arbitrary code execution on its own, it can serve as a stepping stone for more sophisticated attacks by revealing memory layout details or sensitive data that could be leveraged in combination with other vulnerabilities.
The operational impact of this vulnerability extends beyond simple information disclosure, as it represents a potential precursor to more severe exploitation techniques within the context of the ATT&CK framework's initial access and execution phases. An attacker could potentially combine this vulnerability with other exploits to achieve arbitrary code execution, particularly through techniques involving heap spraying or memory corruption attacks that rely on knowing the memory layout of the target application. The fact that this vulnerability affects PDF-XChange Editor specifically means that organizations using this software for document processing are at risk, particularly in environments where users may encounter malicious files through email attachments, web downloads, or compromised websites. The ZDI-CAN-20620 reference indicates this vulnerability was identified through coordinated disclosure channels, highlighting the importance of timely patch management and vulnerability assessment practices.
Mitigation strategies should focus on immediate patch application from the vendor, as well as implementing defensive measures such as restricting file type handling in web browsers and email clients, deploying sandboxing mechanisms for document processing, and monitoring for suspicious file access patterns. Organizations should also consider network-based controls that can detect and block malicious EMF file content, particularly when these files are encountered in contexts where user interaction is required. The vulnerability underscores the necessity of robust input validation and bounds checking in file format parsers, as well as the importance of regular security assessments of document processing software used in enterprise environments. Implementing principle of least privilege for document handling applications and maintaining up-to-date security patches across all software components remains crucial for defending against this class of vulnerabilities that can enable broader exploitation attempts.