CVE-2018-14946 in PDF2JSON
Summary
by MITRE
An issue has been found in PDF2JSON 0.69. The HtmlString class in ImgOutputDev.cc has Mismatched Memory Management Routines (malloc versus operator delete).
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Analysis
by VulDB Data Team • 04/29/2023
The vulnerability identified as CVE-2018-14946 resides within the PDF2JSON 0.69 software package, specifically within the HtmlString class implementation in the ImgOutputDev.cc source file. This issue represents a critical memory management flaw that arises from the improper handling of dynamic memory allocation and deallocation operations. The problem manifests when the software employs malloc for memory allocation but subsequently uses operator delete for memory deallocation, creating a fundamental mismatch in the memory management routines.
This mismatched memory management routine vulnerability falls under the broader category of CWE-401, which specifically addresses memory leaks and improper memory management practices. The flaw occurs when the software allocates memory using malloc, which is typically associated with C-style memory management, but then attempts to free that memory using operator delete, which is the C++ operator for deallocation. This inconsistency can lead to undefined behavior and potential system instability. The vulnerability is particularly concerning because it affects the core memory management operations within the PDF processing pipeline, where the HtmlString class handles the conversion of PDF elements into HTML format for JSON output.
The operational impact of this vulnerability extends beyond simple memory corruption, potentially enabling attackers to exploit the memory management inconsistency for more serious security breaches. When mismatched memory management routines occur, the application may experience crashes, data corruption, or even arbitrary code execution depending on the specific circumstances of memory layout and allocation patterns. The vulnerability affects the software's ability to properly process PDF files and generate accurate JSON output containing HTML representations of the document elements. This creates a risk that legitimate PDF processing operations could be disrupted or that malicious inputs could trigger the memory management inconsistency to cause more severe system compromise.
Mitigation strategies for CVE-2018-14946 should focus on correcting the memory management practices within the affected software components. The most effective approach involves ensuring consistent memory allocation and deallocation patterns throughout the codebase, specifically requiring that malloc calls be paired with free calls and new expressions be paired with delete operators. Developers should implement proper code reviews and static analysis tools to identify similar memory management inconsistencies across the entire codebase. Additionally, upgrading to a patched version of PDF2JSON that addresses this specific memory management issue would provide the most reliable remediation. The vulnerability also highlights the importance of following secure coding practices as outlined in the software security guidelines and could be addressed through comprehensive testing methodologies including memory leak detection tools and dynamic analysis frameworks that are commonly referenced in the ATT&CK framework for identifying system-level vulnerabilities.