EUVD-2025-19146
CVSS Vector
CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Lifecycle Timeline
3Description
PDF-XChange Editor U3D File Parsing Use-After-Free 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 validating the existence of an object prior to performing operations on the object. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-26536.
Analysis
CVE-2025-6644 is a use-after-free vulnerability in PDF-XChange Editor's U3D file parser that allows remote code execution with high severity (CVSS 7.8). The vulnerability affects PDF-XChange Editor across multiple versions when processing malicious U3D-embedded PDF files or standalone U3D files, requiring only user interaction to exploit. The flaw stems from insufficient object validation before dereferencing, enabling attackers to execute arbitrary code in the application context; exploitation likelihood and active KEV status would indicate real-world threat priority.
Technical Context
The vulnerability exists in PDF-XChange Editor's implementation of U3D (Universal 3D) file format parsing, a standard for embedding 3D models within PDF documents (ISO/IEC 14496-17). The root cause is CWE-416 (Use-After-Free), a memory safety issue where the parser attempts operations on object references without validating object existence post-allocation. This occurs during U3D stream deserialization within PDF processing pipelines. The parser fails to implement proper object lifecycle management and reference counting, allowing an attacker to craft a malicious U3D structure that references already-freed memory regions. When the parser subsequently attempts to read or manipulate freed object properties, it operates on attacker-controlled memory, enabling heap exploitation techniques. The vulnerability was originally identified as ZDI-CAN-26536 by Trend Micro's Zero Day Initiative, indicating professional security research classification.
Affected Products
PDF-XChange Editor (all versions vulnerable to U3D parsing prior to patch release; specific version cutoff requires vendor advisory). CPE identifier likely follows pattern: cpe:2.3:a:tracker-software:pdf-xchange_editor:*:*:*:*:*:*:*:* with version constraints pending vendor patch documentation. Affected configurations include: (1) PDF-XChange Editor Desktop Application on Windows; (2) Any system where PDF-XChange Editor processes untrusted PDF files containing embedded U3D objects; (3) Email clients or web browsers configured to open PDFs with PDF-XChange Editor. Secondary risk exists for any application using PDF-XChange Editor SDK/libraries for U3D parsing. Vendor advisory from Tracker Software Products is authoritative source for precise version ranges and patched releases.
Remediation
Immediate actions: (1) Update PDF-XChange Editor to the latest patched version released by Tracker Software Products (consult vendor security advisory for specific version number, likely 10.x.x or higher); (2) Implement file-type restrictions preventing PDF-XChange Editor from processing U3D-embedded PDFs if patched version unavailable; (3) User education: avoid opening unsolicited PDFs from untrusted sources, particularly via email. Workarounds if patch unavailable: (a) disable U3D support in PDF-XChange Editor settings if configurable; (b) use alternative PDF viewers (Adobe Reader DC, Foxit Reader) for untrusted files pending patch release; (c) employ sandboxing (Windows Sandbox, virtualization) for opening suspicious PDFs. Enterprise mitigation: deploy application whitelisting to restrict PDF-XChange Editor execution, implement email gateway scanning for embedded U3D objects, and monitor for abnormal process spawning from PDF-XChange Editor processes. Monitor Tracker Software Products official security page and advisories for patch ETA and technical details.
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External POC / Exploit Code
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