CVE-2025-6647 in PDF-XChange
Summary
by MITRE • 06/26/2025
PDF-XChange Editor U3D File Parsing Out-Of-Bounds Write Remote Code Execution Vulnerability. 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 U3D files. 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 object. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-26644.
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Analysis
by VulDB Data Team • 07/02/2025
This vulnerability resides in PDF-XChange Editor's handling of U3D (Universal 3D) files, representing a critical out-of-bounds write condition that enables remote code execution. The flaw manifests during the parsing of U3D file structures where insufficient input validation permits malicious data to overwrite memory regions beyond the intended allocation boundaries. This type of vulnerability falls under CWE-787 Out-of-bounds Write, which is classified as a severe memory corruption issue that can lead to arbitrary code execution. The vulnerability requires user interaction to exploit, meaning an attacker must convince a victim to open a malicious U3D file or visit a compromised webpage containing such content, making it a remote code execution vector that operates through social engineering or drive-by download attacks.
The technical implementation of this vulnerability involves the improper bounds checking within the U3D file parser component of PDF-XChange Editor. When processing malformed U3D file structures, the application fails to validate array indices or buffer sizes before performing write operations, allowing attackers to craft malicious U3D files that trigger memory corruption. This memory corruption can overwrite critical program data structures, function pointers, or return addresses, ultimately enabling attackers to redirect execution flow and inject malicious code. The vulnerability operates at the application level and can be exploited to achieve code execution with the privileges of the running PDF-XChange Editor process, potentially leading to full system compromise if the application runs with elevated permissions.
The operational impact of this vulnerability extends beyond simple code execution, as it represents a significant threat to enterprise security environments where PDF processing is common. Attackers can leverage this vulnerability to establish persistent access through the execution of malicious payloads that may include backdoors, information stealers, or additional exploitation components. The remote nature of the attack means that organizations are vulnerable even when users are not actively engaged with potentially malicious content, as simply visiting a compromised website or opening a malicious document can trigger exploitation. This vulnerability aligns with ATT&CK technique T1203 Exploitation for Client Execution, where adversaries leverage application vulnerabilities to execute code on target systems. Organizations using PDF-XChange Editor are at risk of supply chain attacks, as malicious actors could compromise legitimate websites or document repositories to deliver these exploit payloads.
Mitigation strategies should focus on immediate patching of the affected software version, as the vulnerability is likely addressed through proper bounds checking and input validation mechanisms. System administrators should implement network-based protections such as web application firewalls and content filtering to block access to known malicious U3D files or suspicious websites. Additionally, user education and awareness programs should emphasize the dangers of opening untrusted documents, particularly those containing 3D content or complex file formats. The vulnerability demonstrates the importance of input validation and memory safety practices, which aligns with secure coding guidelines such as those recommended in the OWASP Secure Coding Practices and the CERT Secure Coding Standards. Organizations should also consider implementing application whitelisting policies that restrict the execution of PDF-XChange Editor to trusted environments and monitor for unusual file access patterns that might indicate exploitation attempts.