CVE-2016-5646 in Perceptive Document Filters Library
Summary
by MITRE
An exploitable heap overflow vulnerability exists in the Compound Binary File Format (CBFF) parser functionality of Lexmark Perceptive Document Filters library. A specially crafted CBFF file can cause a code execution. An attacker can send a malformed file to trigger this vulnerability.
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Analysis
by VulDB Data Team • 04/20/2025
The vulnerability identified as CVE-2016-5646 represents a critical heap overflow condition within the Compound Binary File Format parser component of Lexmark Perceptive Document Filters library. This flaw resides in the handling of structured storage files that follow the Microsoft Compound File Binary Format specification, commonly used for document storage in various enterprise applications. The vulnerability manifests when the parser processes malformed CBFF files that contain overly large or malformed data structures within the compound file's internal structure, leading to memory corruption that can be exploited for arbitrary code execution.
The technical implementation of this vulnerability stems from inadequate bounds checking and memory management within the CBFF parser logic. When processing a specially crafted compound file, the parser fails to properly validate the size parameters of various internal structures such as directory entries, sector allocation tables, or stream data structures. This lack of proper input validation allows an attacker to manipulate the parsing process by embedding malicious size values that cause the heap allocator to allocate insufficient memory for data structures, subsequently leading to buffer overflows when the parser attempts to write beyond allocated memory boundaries. The vulnerability is classified as a heap-based buffer overflow under CWE-121, representing a fundamental memory safety issue where the heap memory management fails to prevent writes beyond allocated buffer limits.
The operational impact of this vulnerability extends beyond simple code execution capabilities to encompass potential system compromise and unauthorized access. Attackers can leverage this vulnerability to execute arbitrary code with the privileges of the affected application, typically resulting in full system compromise when the application runs with elevated permissions. The attack vector requires only the delivery of a maliciously crafted CBFF file, making it particularly dangerous in environments where users may encounter such files through email attachments, document sharing, or web-based document processing. The vulnerability affects systems running Lexmark Perceptive Document Filters, which are commonly deployed in enterprise environments for document processing and conversion, making it a significant threat to organizational security infrastructure.
Mitigation strategies for CVE-2016-5646 should focus on both immediate patching and defensive measures. The primary solution involves applying the vendor-supplied security patches that address the memory handling issues within the CBFF parser implementation. Organizations should also implement file validation controls that scan incoming documents for malformed CBFF structures before processing, utilizing signature-based detection mechanisms or behavioral analysis to identify potentially malicious files. Network-level controls including content filtering and sandboxing of document processing workflows can provide additional defense in depth. From an ATT&CK perspective, this vulnerability maps to techniques involving malicious file execution and privilege escalation, with potential lateral movement capabilities when exploited in enterprise environments. The vulnerability demonstrates the importance of secure coding practices and proper input validation, particularly in libraries that process untrusted binary data formats, aligning with defensive strategies outlined in the MITRE ATT&CK framework for preventing code injection and memory corruption attacks.