CVE-2022-42405 in PDF-XChange Editor
Summary
by MITRE • 01/26/2023
This vulnerability allows remote attackers to execute arbitrary code 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. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a fixed-length heap-based buffer. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-18367.
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Analysis
by VulDB Data Team • 04/29/2025
CVE-2022-42405 represents a critical buffer overflow vulnerability affecting PDF-XChange Editor version 8.0.0.386 and earlier, classified under CWE-121 as a stack-based buffer overflow. This vulnerability stems from insufficient input validation during the parsing of Enhanced Metafile (EMF) files, which are commonly used for vector graphics within document processing applications. The flaw occurs when the application processes user-supplied EMF data without properly validating the length of the input before copying it into a fixed-size heap-based buffer, creating an exploitable condition that allows attackers to overwrite adjacent memory locations.
The technical implementation of this vulnerability involves the application's failure to perform bounds checking on EMF file data during parsing operations. When PDF-XChange Editor encounters an EMF file, it attempts to copy the data into a predetermined memory buffer without verifying that the source data length exceeds the buffer capacity. This classic buffer overflow condition enables attackers to craft malicious EMF files that, when processed by the vulnerable application, can overwrite critical memory structures including return addresses and function pointers. The vulnerability requires user interaction through either visiting a malicious webpage that loads the EMF file or opening a malicious document containing the crafted EMF content, making it a client-side exploit that leverages social engineering techniques.
The operational impact of this vulnerability extends beyond simple code execution, as it allows attackers to operate within the security context of the currently running process with the same privileges as the PDF-XChange Editor application. This presents a significant risk for privilege escalation attacks, particularly when the application runs with elevated permissions or accesses sensitive system resources. Attackers can leverage this vulnerability to execute arbitrary code, potentially leading to full system compromise, data exfiltration, or installation of persistent backdoors. The exploitability of this vulnerability aligns with ATT&CK technique T1059.007 for command and script interpreter execution, as successful exploitation would enable attackers to execute malicious commands through the compromised application process.
The security implications of CVE-2022-42405 demonstrate the critical importance of proper input validation in document processing applications that handle external file formats. This vulnerability highlights the risks associated with processing untrusted vector graphics formats within office applications, as EMF files can contain complex graphical instructions that, when improperly validated, create opportunities for memory corruption attacks. Organizations using PDF-XChange Editor should prioritize immediate patching to address this vulnerability, as the combination of remote exploitability and the requirement for minimal user interaction makes it particularly dangerous in targeted attack scenarios. The vulnerability also underscores the need for robust application sandboxing and privilege separation techniques to limit the potential damage from successful exploitation attempts.