CVE-2016-10246 in MuPDF
Summary
by MITRE
Buffer overflow in the main function in jstest_main.c in Mujstest in Artifex Software, Inc. MuPDF before 1.10 allows remote attackers to cause a denial of service (out-of-bounds write) via a crafted file.
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Analysis
by VulDB Data Team • 09/12/2024
The vulnerability identified as CVE-2016-10246 represents a critical buffer overflow flaw within the MuPDF document processing library developed by Artifex Software. This issue specifically affects the jstest_main.c component where the main function handles input processing, creating a scenario where maliciously crafted PDF files can trigger memory corruption. The vulnerability exists in MuPDF versions prior to 1.10, making a substantial portion of deployed systems susceptible to exploitation. The buffer overflow occurs during the parsing of JavaScript elements within PDF documents, where insufficient input validation allows attackers to write beyond allocated memory boundaries.
The technical implementation of this vulnerability stems from inadequate bounds checking in the JavaScript execution environment within MuPDF. When processing a specially crafted PDF file containing malformed JavaScript code, the application fails to properly validate the size and structure of input data before attempting to write to memory locations. This flaw manifests as an out-of-bounds write condition that can be leveraged to crash the application or potentially execute arbitrary code depending on memory layout and exploitation circumstances. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, though it operates within the context of a heap-based memory corruption scenario typical of modern document processing exploits. The flaw demonstrates poor input sanitization practices that violate secure coding principles and can be categorized under ATT&CK technique T1059.007 for JavaScript-based execution.
The operational impact of this vulnerability extends beyond simple denial of service, as it creates opportunities for more sophisticated attacks that could compromise system integrity. Remote attackers can exploit this weakness by delivering malicious PDF files through various attack vectors including email attachments, web downloads, or malicious websites. The nature of the vulnerability means that any system running affected versions of MuPDF is at risk, particularly those that process untrusted PDF content such as email servers, web applications, and document management systems. When exploited, the vulnerability can cause applications to crash repeatedly, leading to service disruption and potential data loss. Organizations relying on MuPDF for document rendering, viewing, or processing operations face significant risk of operational downtime and potential security breaches.
Mitigation strategies for CVE-2016-10246 require immediate patching of all affected MuPDF installations to version 1.10 or later where the buffer overflow has been addressed. System administrators should implement strict input validation policies for all PDF processing workflows and consider deploying sandboxing mechanisms to isolate document rendering operations. Network-level protections such as web application firewalls and content filtering systems can help prevent delivery of malicious PDF files to end users. Organizations should also conduct comprehensive vulnerability assessments to identify all systems running affected MuPDF versions and establish monitoring procedures to detect potential exploitation attempts. The fix implemented by Artifex Software addresses the root cause by adding proper bounds checking and input validation mechanisms, ensuring that JavaScript execution elements are properly validated before memory allocation occurs. Regular security updates and vulnerability management programs should be maintained to prevent similar issues from arising in future versions of document processing libraries.