CVE-2022-42407 in PDF-XChange Editor
Summary
by MITRE • 01/26/2023
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-18542.
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Analysis
by VulDB Data Team • 04/29/2025
CVE-2022-42407 represents a critical buffer overread vulnerability affecting PDF-XChange Editor versions up to 9.5.343. This weakness resides in the software's handling of EMF (Enhanced Metafile) files during the parsing process, specifically when processing crafted data within these file formats. The vulnerability manifests when the application attempts to read data beyond the boundaries of an allocated memory buffer, creating a condition where adjacent memory locations can be accessed and potentially disclosed. This type of flaw falls under CWE-125, known as "Out-of-bounds Read," which is classified as a common weakness in software security implementations. The vulnerability requires user interaction to be exploited, making it particularly dangerous as it can be triggered through web browsing or file opening activities, aligning with ATT&CK technique T1203 for "Exploitation for Client Execution."
The technical implementation of this vulnerability involves the improper validation of EMF file structures during parsing operations. When PDF-XChange Editor encounters an EMF file containing maliciously crafted data, the parsing routine fails to properly bounds-check memory accesses, allowing for a read past the end of allocated buffer space. This condition can result in information disclosure, as the application may inadvertently expose sensitive data from adjacent memory regions that could contain credentials, encryption keys, or other confidential information. The vulnerability's exploitation potential extends beyond simple information disclosure, as demonstrated by the advisory mentioning that attackers can leverage this weakness in conjunction with other vulnerabilities to achieve arbitrary code execution within the context of the current process, representing a path toward privilege escalation and system compromise.
The operational impact of CVE-2022-42407 is significant for organizations relying on PDF-XChange Editor for document processing and viewing. Attackers can craft malicious EMF files that, when opened or viewed within the application, trigger the buffer overread condition. This vulnerability affects both web-based and local file execution scenarios, making it particularly dangerous in enterprise environments where users may encounter malicious content through email attachments, web downloads, or file sharing systems. The vulnerability's classification as a remote code execution risk through combination with other exploits indicates that it could serve as a critical initial access vector in multi-stage attack campaigns. Organizations using PDF-XChange Editor should consider implementing additional security controls such as application whitelisting, sandboxing, and network-based protection mechanisms to mitigate the risk of exploitation.
Mitigation strategies for CVE-2022-42407 should prioritize immediate software updates from the vendor to address the underlying buffer overread condition in EMF file parsing. System administrators should implement strict file access controls and user education programs to reduce the likelihood of users encountering malicious EMF files through untrusted sources. Network security measures including web proxies, content filtering, and email security gateways should be configured to block or scan EMF file attachments and embedded content. Additionally, organizations should consider deploying application isolation techniques and memory protection mechanisms such as address space layout randomization and data execution prevention to limit the potential impact if exploitation occurs. The vulnerability's relationship to the broader ATT&CK framework highlights the importance of implementing comprehensive defensive strategies that address both the specific technical flaw and the broader threat landscape of exploitation techniques targeting document processing applications.