CVE-2019-14290 in Xpdf
Summary
by MITRE
An issue was discovered in Xpdf 4.01.01. There is an out of bounds read in the function GfxPatchMeshShading::parse at GfxState.cc for typeA==6 case 2.
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Analysis
by VulDB Data Team • 08/29/2025
The vulnerability identified as CVE-2019-14290 represents a critical out-of-bounds read condition within the Xpdf 4.01.01 document rendering library. This flaw exists specifically within the GfxPatchMeshShading::parse function located in the GfxState.cc source file, where the software fails to properly validate input data when processing certain shading types. The issue manifests exclusively in the typeA==6 case, specifically case 2, indicating that the vulnerability is triggered by particular shading parameters that define how color gradients are rendered in PDF documents. The out-of-bounds read occurs when the application attempts to access memory locations beyond the allocated buffer boundaries while parsing patch mesh shading data, creating a potential avenue for arbitrary code execution or information disclosure.
This vulnerability falls under the CWE-125 weakness category, which specifically addresses out-of-bounds read conditions in software implementations. The flaw represents a classic buffer overread scenario where the Xpdf library does not perform adequate bounds checking on array indices or memory access patterns during PDF shading parsing operations. The attack surface is particularly concerning as PDF rendering libraries are extensively used across multiple platforms and applications, making this vulnerability exploitable in numerous real-world scenarios. The vulnerability's impact is amplified by the fact that it occurs during normal document parsing operations, meaning that simply opening a maliciously crafted PDF file could trigger the exploit without requiring user interaction beyond the initial document opening.
The operational impact of CVE-2019-14290 extends beyond simple denial of service conditions to potentially enable remote code execution in vulnerable environments. When an attacker crafts a PDF document containing maliciously formatted patch mesh shading data with typeA==6 and case 2 parameters, the vulnerable Xpdf library will attempt to read memory beyond allocated boundaries, potentially causing application crashes or allowing attackers to extract sensitive information from memory. This type of vulnerability aligns with ATT&CK technique T1203, which covers exploitation of software vulnerabilities for privilege escalation or information gathering. The vulnerability is particularly dangerous in web-based PDF viewers, email clients, and document management systems that utilize Xpdf for rendering PDF content, as these applications are frequently targeted by adversaries seeking to exploit such rendering library vulnerabilities.
Mitigation strategies for CVE-2019-14290 should prioritize immediate patching of affected Xpdf installations to version 4.01.02 or later, which contains the necessary fixes for the out-of-bounds read condition. Organizations should implement defensive measures such as PDF sandboxing, content filtering, and restricted file type handling to limit exposure to potentially malicious documents. Additionally, regular security assessments of PDF rendering components and monitoring for unusual memory access patterns during document processing can help detect exploitation attempts. The vulnerability demonstrates the importance of proper input validation and bounds checking in graphics rendering libraries, particularly those handling complex data structures like patch mesh shading. Security teams should also consider implementing network-level controls to restrict access to PDF processing capabilities where possible, reducing the attack surface for this and similar vulnerabilities.